Discussion:
simple ping; pinging 101
(too old to reply)
THUFIR HAWAT
2005-07-06 11:40:07 UTC
Permalink
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.

what's wrong with arrakis eth1, please?

I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.


arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102

terminal stuff from arrakis:

[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms

--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes

[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400

eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)

[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#

[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes

[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400

eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)

[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#


links:

arrakis mother board:
<http://www.ecsusa.com/downloads/manual_k7s.html>

eth1 NIC on arrakis:
<http://www.dlink.ca/product.php?PID=124>



thanks,

Thufir
Ow Mun Heng
2005-07-06 11:49:08 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.

To be sure.. switch the cables or switch the IPs (better)
Post by THUFIR HAWAT
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
Why is there no default route??
THUFIR HAWAT
2005-07-06 12:18:50 UTC
Permalink
On 7/6/05, Ow Mun Heng <Ow.Mun.Heng at wdc.com> wrote:
...
Post by Ow Mun Heng
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.
To be sure.. switch the cables or switch the IPs (better)
I'm not sure what's meant by switching the cables. either arrakis
eth0 or arrakis eth1 is connected to the hub, never both
simultaneously. pardon if that wasn't clear.

the IP's are entirely arbitrary, how would switching the IP address
for arrakis eth0 and eth1 change anything?

...
Post by Ow Mun Heng
Why is there no default route??
what's a default route? seriously :)


thanks,

Thufir
Ow Mun Heng
2005-07-06 13:18:03 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Ow Mun Heng
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.
To be sure.. switch the cables or switch the IPs (better)
I'm not sure what's meant by switching the cables. either arrakis
eth0 or arrakis eth1 is connected to the hub, never both
simultaneously. pardon if that wasn't clear.
No it wasn't :-)
Post by THUFIR HAWAT
the IP's are entirely arbitrary, how would switching the IP address
for arrakis eth0 and eth1 change anything
I initially assumed it was because of the connection and One IP worked
and the other didn't
Post by THUFIR HAWAT
...
Post by Ow Mun Heng
Why is there no default route??
what's a default route? seriously :)
$route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.83.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
172.16.124.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet8
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
loopback 0.0.0.0 255.0.0.0 U 0 0 0 lo
default 192.168.10.1 0.0.0.0 UG 0 0 0 eth1


The default route is to tell the interface which eth to send the packets
to.
--
Ow Mun Heng
Gentoo/Linux on DELL D600 1.4Ghz 1.5GB RAM
98% Microsoft(tm) Free!!
Neuromancer 21:18:02 up 2 days, 1:05, 5 users, load average: 0.55, 0.97,
0.79
Ow Mun Heng
2005-07-06 13:18:03 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Ow Mun Heng
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.
To be sure.. switch the cables or switch the IPs (better)
I'm not sure what's meant by switching the cables. either arrakis
eth0 or arrakis eth1 is connected to the hub, never both
simultaneously. pardon if that wasn't clear.
No it wasn't :-)
Post by THUFIR HAWAT
the IP's are entirely arbitrary, how would switching the IP address
for arrakis eth0 and eth1 change anything
I initially assumed it was because of the connection and One IP worked
and the other didn't
Post by THUFIR HAWAT
...
Post by Ow Mun Heng
Why is there no default route??
what's a default route? seriously :)
$route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.83.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
172.16.124.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet8
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
loopback 0.0.0.0 255.0.0.0 U 0 0 0 lo
default 192.168.10.1 0.0.0.0 UG 0 0 0 eth1


The default route is to tell the interface which eth to send the packets
to.
--
Ow Mun Heng
Gentoo/Linux on DELL D600 1.4Ghz 1.5GB RAM
98% Microsoft(tm) Free!!
Neuromancer 21:18:02 up 2 days, 1:05, 5 users, load average: 0.55, 0.97,
0.79
THUFIR HAWAT
2005-07-06 12:18:50 UTC
Permalink
On 7/6/05, Ow Mun Heng <Ow.Mun.Heng at wdc.com> wrote:
...
Post by Ow Mun Heng
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.
To be sure.. switch the cables or switch the IPs (better)
I'm not sure what's meant by switching the cables. either arrakis
eth0 or arrakis eth1 is connected to the hub, never both
simultaneously. pardon if that wasn't clear.

the IP's are entirely arbitrary, how would switching the IP address
for arrakis eth0 and eth1 change anything?

...
Post by Ow Mun Heng
Why is there no default route??
what's a default route? seriously :)


thanks,

Thufir
Lai Zit Seng
2005-07-06 12:01:23 UTC
Permalink
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.

Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!

Regards,

.lzs
--
http://zitseng.com/
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms
--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
<http://www.ecsusa.com/downloads/manual_k7s.html>
<http://www.dlink.ca/product.php?PID=124>
thanks,
Thufir
THUFIR HAWAT
2005-07-06 12:13:48 UTC
Permalink
Post by Lai Zit Seng
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.
Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!
...

if you understand me and I understand you, then yes ;)

when the cable is plugged into eth0, and the network script on arrakis
is restarted, then arrakis can ping caladan.

when the cable is plugged into eth1 and the same procedure is followed
then the ping fails. if the cable is then plugged into eth0 and the
network script restarted then the ping succeeds again.

what's wrong with the "experiment"? it seems to me that there's a
problem with eth1.

the immediate goal is to ping from arrakis eth1 to caladan.


thanks,

Thufir
Lai Zit Seng
2005-07-07 01:07:54 UTC
Permalink
Post by THUFIR HAWAT
Post by Lai Zit Seng
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.
Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!
...
if you understand me and I understand you, then yes ;)
when the cable is plugged into eth0, and the network script on arrakis
is restarted, then arrakis can ping caladan.
when the cable is plugged into eth1 and the same procedure is followed
then the ping fails. if the cable is then plugged into eth0 and the
network script restarted then the ping succeeds again.
what's wrong with the "experiment"? it seems to me that there's a
problem with eth1.
the immediate goal is to ping from arrakis eth1 to caladan.
Nothing's wrong with the experiment. You just can't do it like this :)
Ok, I'll cut short my reply since many others have followed-up.

It looks to me like you're trying to have "redundant" network
connections for, perhaps, high-availability reasons. I.e. you still have
network access should one link fail.

Also as others have mentioned, you'll need to bind the interfaces
together, and needs similar support on the switch side. E.g. this is
called EtherChannel in Cisco switches.

An alternative is to setup bridging on your systems. This is even better
actually since now each system can connect to two separate switches, all
hooked up in a redundant configuration, and running spanning tree
protocol to eliminate forwarding loops. Then your IP interface itself
will be on the bridge device.

Yes all these start to get more complicated :) But there should be
HOW-TOs you can google for :)

Regards,

.lzs
--
http://zitseng.com/
Post by THUFIR HAWAT
thanks,
Thufir
THUFIR HAWAT
2005-07-07 05:41:51 UTC
Permalink
On 7/6/05, Lai Zit Seng <lzs at pobox.com> wrote:
...
Post by Lai Zit Seng
Nothing's wrong with the experiment. You just can't do it like this :)
Ok, I'll cut short my reply since many others have followed-up.
It looks to me like you're trying to have "redundant" network
connections for, perhaps, high-availability reasons. I.e. you still have
network access should one link fail.
...

sorry to have given that impression, I'm not trying for redundant
network connections. I suppose I'm just gathering data in order to
learn about ping.

glad to know that my experiment is doomed to failure, that's valuable
data (err, that might sound sarcastic but I'm serious).

since the experiment is flawed, I'll drop it in favor of two
experiments. experiments #1 and #2 are, lets say, unrelated to each
other.

experiment #1:

ping from the arrakis built-in NIC to caladan.


experiment #2:

ping from the arrakis D-Link NIC to caladan.

there are obvious similarities, but for my purposes the experiments
are totally independant of each other.

All I'm looking for at this stage is to be able to reproduce the
(succesful) results. is that a better approach?

thanks,

Thufir
Lai Zit Seng
2005-07-07 06:06:35 UTC
Permalink
Post by THUFIR HAWAT
glad to know that my experiment is doomed to failure, that's valuable
data (err, that might sound sarcastic but I'm serious).
Having any results is valuable :)
Post by THUFIR HAWAT
since the experiment is flawed, I'll drop it in favor of two
experiments. experiments #1 and #2 are, lets say, unrelated to each
other.
ping from the arrakis built-in NIC to caladan.
ping from the arrakis D-Link NIC to caladan.
there are obvious similarities, but for my purposes the experiments
are totally independant of each other.
All I'm looking for at this stage is to be able to reproduce the
(succesful) results. is that a better approach?
In this case, it is probably best to simply 'up' only specifically the
network interface of the respective NIC you want the experiment to use :)

What are the experiments supposed to achieve/demonstrate/etc? Perhaps you
could consider to use different subnet addresses, one each for the NICs on
arrakis, and then both subnet addresses configured together (ip aliasing)
on the same interface of caladan.

Regards,

.lzs
THUFIR HAWAT
2005-07-07 07:57:20 UTC
Permalink
On 7/6/05, Lai Zit Seng <lzs at pobox.com> wrote:
...
Post by Lai Zit Seng
In this case, it is probably best to simply 'up' only specifically the
network interface of the respective NIC you want the experiment to use :)
ok, I follow you there. The intent of having two distinct experiments
is to isolate the two NIC's, so disabling one of the NIC's certainly
makes sense in that context.
Post by Lai Zit Seng
What are the experiments supposed to achieve/demonstrate/etc? Perhaps you
could consider to use different subnet addresses, one each for the NICs on
arrakis, and then both subnet addresses configured together (ip aliasing)
on the same interface of caladan.
sure, the IP addresses are completly arbitrary at this stage.
basically, though, you're over my head with that.

what's the purpose of the experiments?
the intent is to twofold: to test the hardware and to create a
baseline. for instance, I started with a crossover cable because the
hub was old, used and an unknown. also, it wasn't always clear that
both NIC's actually worked. I've now established that the hub works,
so I can get rid of the crossover cable. IP masquerading, DHCP are a
bit much for me at the moment. being able to reliably send a ping
from either arrakis NIC will always be something to come back to. If
I can do that then I'll be more comfortable with adding IP aliasing,
DHCP, etc on top of that foundation. alternatively, if I can't
reliably ping it seems to me that everything would be built on a shaky
foundation. ping seems to be the base for everything else. the
various settings might be drastically different, of course.

this is why my initial question was:

"what's wrong with arrakis eth1, please?"

and it appears that the routing and arrakis eth0 are interfering with
arrakis eth1. so, to "fix" arrakis eth1, sure, disable arrakis eth0
and change the routing. (and vice versa for the other NIC in
arrakis.) in retrospect, a better question would've been "how can
arrakis ping caladan from the D-Link NIC?" followed by "how can
arrakis ping caladan from the built in NIC?"


thanks,

Thufir
THUFIR HAWAT
2005-07-07 07:57:20 UTC
Permalink
On 7/6/05, Lai Zit Seng <lzs at pobox.com> wrote:
...
Post by Lai Zit Seng
In this case, it is probably best to simply 'up' only specifically the
network interface of the respective NIC you want the experiment to use :)
ok, I follow you there. The intent of having two distinct experiments
is to isolate the two NIC's, so disabling one of the NIC's certainly
makes sense in that context.
Post by Lai Zit Seng
What are the experiments supposed to achieve/demonstrate/etc? Perhaps you
could consider to use different subnet addresses, one each for the NICs on
arrakis, and then both subnet addresses configured together (ip aliasing)
on the same interface of caladan.
sure, the IP addresses are completly arbitrary at this stage.
basically, though, you're over my head with that.

what's the purpose of the experiments?
the intent is to twofold: to test the hardware and to create a
baseline. for instance, I started with a crossover cable because the
hub was old, used and an unknown. also, it wasn't always clear that
both NIC's actually worked. I've now established that the hub works,
so I can get rid of the crossover cable. IP masquerading, DHCP are a
bit much for me at the moment. being able to reliably send a ping
from either arrakis NIC will always be something to come back to. If
I can do that then I'll be more comfortable with adding IP aliasing,
DHCP, etc on top of that foundation. alternatively, if I can't
reliably ping it seems to me that everything would be built on a shaky
foundation. ping seems to be the base for everything else. the
various settings might be drastically different, of course.

this is why my initial question was:

"what's wrong with arrakis eth1, please?"

and it appears that the routing and arrakis eth0 are interfering with
arrakis eth1. so, to "fix" arrakis eth1, sure, disable arrakis eth0
and change the routing. (and vice versa for the other NIC in
arrakis.) in retrospect, a better question would've been "how can
arrakis ping caladan from the D-Link NIC?" followed by "how can
arrakis ping caladan from the built in NIC?"


thanks,

Thufir
Lai Zit Seng
2005-07-07 06:06:35 UTC
Permalink
Post by THUFIR HAWAT
glad to know that my experiment is doomed to failure, that's valuable
data (err, that might sound sarcastic but I'm serious).
Having any results is valuable :)
Post by THUFIR HAWAT
since the experiment is flawed, I'll drop it in favor of two
experiments. experiments #1 and #2 are, lets say, unrelated to each
other.
ping from the arrakis built-in NIC to caladan.
ping from the arrakis D-Link NIC to caladan.
there are obvious similarities, but for my purposes the experiments
are totally independant of each other.
All I'm looking for at this stage is to be able to reproduce the
(succesful) results. is that a better approach?
In this case, it is probably best to simply 'up' only specifically the
network interface of the respective NIC you want the experiment to use :)

What are the experiments supposed to achieve/demonstrate/etc? Perhaps you
could consider to use different subnet addresses, one each for the NICs on
arrakis, and then both subnet addresses configured together (ip aliasing)
on the same interface of caladan.

Regards,

.lzs
THUFIR HAWAT
2005-07-07 05:41:51 UTC
Permalink
On 7/6/05, Lai Zit Seng <lzs at pobox.com> wrote:
...
Post by Lai Zit Seng
Nothing's wrong with the experiment. You just can't do it like this :)
Ok, I'll cut short my reply since many others have followed-up.
It looks to me like you're trying to have "redundant" network
connections for, perhaps, high-availability reasons. I.e. you still have
network access should one link fail.
...

sorry to have given that impression, I'm not trying for redundant
network connections. I suppose I'm just gathering data in order to
learn about ping.

glad to know that my experiment is doomed to failure, that's valuable
data (err, that might sound sarcastic but I'm serious).

since the experiment is flawed, I'll drop it in favor of two
experiments. experiments #1 and #2 are, lets say, unrelated to each
other.

experiment #1:

ping from the arrakis built-in NIC to caladan.


experiment #2:

ping from the arrakis D-Link NIC to caladan.

there are obvious similarities, but for my purposes the experiments
are totally independant of each other.

All I'm looking for at this stage is to be able to reproduce the
(succesful) results. is that a better approach?

thanks,

Thufir
Lai Zit Seng
2005-07-07 01:07:54 UTC
Permalink
Post by THUFIR HAWAT
Post by Lai Zit Seng
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.
Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!
...
if you understand me and I understand you, then yes ;)
when the cable is plugged into eth0, and the network script on arrakis
is restarted, then arrakis can ping caladan.
when the cable is plugged into eth1 and the same procedure is followed
then the ping fails. if the cable is then plugged into eth0 and the
network script restarted then the ping succeeds again.
what's wrong with the "experiment"? it seems to me that there's a
problem with eth1.
the immediate goal is to ping from arrakis eth1 to caladan.
Nothing's wrong with the experiment. You just can't do it like this :)
Ok, I'll cut short my reply since many others have followed-up.

It looks to me like you're trying to have "redundant" network
connections for, perhaps, high-availability reasons. I.e. you still have
network access should one link fail.

Also as others have mentioned, you'll need to bind the interfaces
together, and needs similar support on the switch side. E.g. this is
called EtherChannel in Cisco switches.

An alternative is to setup bridging on your systems. This is even better
actually since now each system can connect to two separate switches, all
hooked up in a redundant configuration, and running spanning tree
protocol to eliminate forwarding loops. Then your IP interface itself
will be on the bridge device.

Yes all these start to get more complicated :) But there should be
HOW-TOs you can google for :)

Regards,

.lzs
--
http://zitseng.com/
Post by THUFIR HAWAT
thanks,
Thufir
THUFIR HAWAT
2005-07-06 12:13:48 UTC
Permalink
Post by Lai Zit Seng
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.
Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!
...

if you understand me and I understand you, then yes ;)

when the cable is plugged into eth0, and the network script on arrakis
is restarted, then arrakis can ping caladan.

when the cable is plugged into eth1 and the same procedure is followed
then the ping fails. if the cable is then plugged into eth0 and the
network script restarted then the ping succeeds again.

what's wrong with the "experiment"? it seems to me that there's a
problem with eth1.

the immediate goal is to ping from arrakis eth1 to caladan.


thanks,

Thufir
Jeff Vian
2005-07-06 12:31:53 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
Probably nothing is wrong except the configuration.

You have 2 NICs on the same subnet. Only one can be the default and in
most flavors of *nix when 2 NICs are on the same subnet the drivers
often get confused and in some cases all communication is either lost or
severely slowed down with this setup.

You can check which the system is using as the default by running
"netstat -r". The Iface column will tell which is the default interface
for the line that starts with default. Your route output below does not
list a default route, and it lists 2 routes to the 192.168.0.0 network.


A very simple test to see which interface is having the problem ( I
don't suspect either) would be to do the following

1. ifdown eth0
2. ping 192.168.0.102
3. ifup eth0
4. ifdown eth1
5. ping 192.168.0.102
6. ifup eth1
7. ping 192.168.0.102

then compare the results of the pings.

I suspect the only one that may have a problem is step 7 when both
interfaces are active.
Post by THUFIR HAWAT
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms
--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
You do not know which interface this went through from this output
Post by THUFIR HAWAT
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
The only one showing a received count is eth0
Post by THUFIR HAWAT
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
No default route? It would have a UG flag
Post by THUFIR HAWAT
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
Now you have done a restart on both interfaces, and eth0 is not seeing
the other machine
Post by THUFIR HAWAT
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000
eth0 still has the only received count. Eth1 has not received a single
packet.

Both show an increase in transmitted, but neither show a change in the
received from the earlier listing.
Post by THUFIR HAWAT
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
<http://www.ecsusa.com/downloads/manual_k7s.html>
<http://www.dlink.ca/product.php?PID=124>
thanks,
Thufir
Scot L. Harris
2005-07-06 15:10:05 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
The problem you are having is shown in the routing table above. Even
when you have one of the two network cables disconnected the routes are
still in the table for both NICs. Since both NICs are in the same
subnet they have routing entries to that subnet.

When you ping with eth0 connected it works. Then when you disconnect
eth0 and connect eth1 and ping it does not work. The reason is that the
ping looks in the routing table and finds the FIRST router to
192.168.0.0 network which is out eth0. But eth0 is not connected to
anything so it fails.

If you completely disable eth0 so that route is not in the route table
eth1 will work.

The real question here is what are you trying to do? Typically you can
not setup two NICs on the same LAN. The only way to do this is to bind
them together to act as a single interface. This will require a switch
that also understands how to bind interfaces/ports together.

You can setup each interface in its own subnet but you will have to have
other devices in the other subnet for it to communicate with.

The other thing that has already been pointed out is that you do not
have a default gateway. The default gateway is used for any packets
going to networks that are not on one of your local LANs. This default
gateway will go out one of the two interfaces not both.

Also note: the 169.254 address if from the zeroconf project and is
useless. This should be disabled by default but it is not. :)
--
Scot L. Harris
webid at cfl.rr.com

Things will be bright in P.M. A cop will shine a light in your face.
THUFIR HAWAT
2005-07-06 15:37:09 UTC
Permalink
On 7/6/05, Scot L. Harris <webid at cfl.rr.com> wrote:
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...

looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>

I've changed the IP addresses as follows:

arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2

to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..

to do do that, is a default gateway required?

I'm just taking this one very small step at a time.


thanks,

Thufir
Alex Evonosky
2005-07-06 15:41:45 UTC
Permalink
Post by THUFIR HAWAT
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
Curious..

Why do you have the same subnet on two interfaces? would it not be
easier to seperate the traffic maybe in /24 or /29 networks to seperate
the traffic on different interfaces?

e.g. All 192.168.0.0/24 traffic on eth1
other networks on different interfaces.
Scot L. Harris
2005-07-06 16:10:25 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
I'm just taking this one very small step at a time.
I think there is a major misunderstanding of what you are trying to do.
In your original message you were trying to setup two interfaces on the
same subnet.

The how to you are following is for setting up a system as a
router/firewall. Each interface on arrakis will be connected to a
different subnet. The one in the example is not what you will use. You
need to use the address that is assigned by your ISP on that interface.
The addressing you have setup on eth1 is fine. That is the only
interface that will be used to communicate with the other systems you
have on your internal LAN.

Your arrakis system will need to have IP forwarding enabled as well as
NAT (masquarading) which the how to you are using should explain.

The arrakis box should end up with a default gateway that points to your
ISPs default gateway system.
--
Scot L. Harris
webid at cfl.rr.com

Life is a POPULARITY CONTEST! I'm REFRESHINGLY CANDID!!
Mike McCarty
2005-07-06 16:21:16 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
I'm just taking this one very small step at a time.
thanks,
Thufir
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.

Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.

Mike
--
p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
This message made from 100% recycled bits.
I can explain it for you, but I can't understand it for you.
I speak only for myself, and I am unanimous in that!
THUFIR HAWAT
2005-07-06 20:47:24 UTC
Permalink
On 7/6/05, Mike McCarty <mike.mccarty at sbcglobal.net> wrote:
...
Post by Mike McCarty
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.
Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.
Mike
I would like to test both arrakis eth1 and arrakis eth0
simultaneously. hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.

absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.

no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?


thanks,

Thufir
Rick Stevens
2005-07-06 21:14:47 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Mike McCarty
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.
Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.
Mike
I would like to test both arrakis eth1 and arrakis eth0
simultaneously. hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.
From arrakis (Muad'Dib):

ping -I eth0 caladan
ping -I eth1 caladan
Post by THUFIR HAWAT
absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.
no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?
thanks,
Thufir
--
----------------------------------------------------------------------
- Rick Stevens, Senior Systems Engineer rstevens at vitalstream.com -
- VitalStream, Inc. http://www.vitalstream.com -
- -
- On a scale of 1 to 10 I'd say... oh, somewhere in there. -
----------------------------------------------------------------------
Kevin J. Cummings
2005-07-09 01:46:27 UTC
Permalink
Post by THUFIR HAWAT
I would like to test both arrakis eth1 and arrakis eth0
simultaneously.
Bad idea. Limit yourself to arrakis eth1 and caladan eth0 first.
Post by THUFIR HAWAT
hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.
absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.
no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?
If you've configured the subnets right, "service network restart" should
set up the proper routing for you. Its a "feature" of the
configuration. Are you using system-config-network to set up the networks?
Post by THUFIR HAWAT
thanks,
Thufir
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
Rick Stevens
2005-07-06 21:14:47 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Mike McCarty
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.
Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.
Mike
I would like to test both arrakis eth1 and arrakis eth0
simultaneously. hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.
From arrakis (Muad'Dib):

ping -I eth0 caladan
ping -I eth1 caladan
Post by THUFIR HAWAT
absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.
no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?
thanks,
Thufir
--
----------------------------------------------------------------------
- Rick Stevens, Senior Systems Engineer rstevens at vitalstream.com -
- VitalStream, Inc. http://www.vitalstream.com -
- -
- On a scale of 1 to 10 I'd say... oh, somewhere in there. -
----------------------------------------------------------------------
Kevin J. Cummings
2005-07-09 01:46:27 UTC
Permalink
Post by THUFIR HAWAT
I would like to test both arrakis eth1 and arrakis eth0
simultaneously.
Bad idea. Limit yourself to arrakis eth1 and caladan eth0 first.
Post by THUFIR HAWAT
hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.
absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.
no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?
If you've configured the subnets right, "service network restart" should
set up the proper routing for you. Its a "feature" of the
configuration. Are you using system-config-network to set up the networks?
Post by THUFIR HAWAT
thanks,
Thufir
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
THUFIR HAWAT
2005-07-06 20:47:24 UTC
Permalink
On 7/6/05, Mike McCarty <mike.mccarty at sbcglobal.net> wrote:
...
Post by Mike McCarty
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.
Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.
Mike
I would like to test both arrakis eth1 and arrakis eth0
simultaneously. hence the attempt to ping caladan from both arrakis
eth0 and arrakis eth1 sequentially.

absolutely, networking is an unknown for me. I'm not trying to setup
masquerading at this point. I'm trying to ping caladan from arrakis
eth1 and arrakis eth0.

no, I do not expect an auto-mount. between pinging from arrakis eth0
and arrakis eth1 attempts I run "./network restart". does the routing
need to be changed at that time as well?


thanks,

Thufir
Kevin J. Cummings
2005-07-09 01:43:13 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth0 192.168.1.1

would have suffuced....
Post by THUFIR HAWAT
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
Connect arrakis eth1 and caladan eth0 to the hub only. If you've done
it right, you should be able to ping both machines from each other....
Post by THUFIR HAWAT
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
No, worry about the default gateway (and forwarding) after your local
subnet is working.
Post by THUFIR HAWAT
I'm just taking this one very small step at a time.
thanks,
Thufir
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
Alex Evonosky
2005-07-06 15:41:45 UTC
Permalink
Post by THUFIR HAWAT
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
Curious..

Why do you have the same subnet on two interfaces? would it not be
easier to seperate the traffic maybe in /24 or /29 networks to seperate
the traffic on different interfaces?

e.g. All 192.168.0.0/24 traffic on eth1
other networks on different interfaces.
Scot L. Harris
2005-07-06 16:10:25 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
I'm just taking this one very small step at a time.
I think there is a major misunderstanding of what you are trying to do.
In your original message you were trying to setup two interfaces on the
same subnet.

The how to you are following is for setting up a system as a
router/firewall. Each interface on arrakis will be connected to a
different subnet. The one in the example is not what you will use. You
need to use the address that is assigned by your ISP on that interface.
The addressing you have setup on eth1 is fine. That is the only
interface that will be used to communicate with the other systems you
have on your internal LAN.

Your arrakis system will need to have IP forwarding enabled as well as
NAT (masquarading) which the how to you are using should explain.

The arrakis box should end up with a default gateway that points to your
ISPs default gateway system.
--
Scot L. Harris
webid at cfl.rr.com

Life is a POPULARITY CONTEST! I'm REFRESHINGLY CANDID!!
Mike McCarty
2005-07-06 16:21:16 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
I'm just taking this one very small step at a time.
thanks,
Thufir
It sounds like you want the OS to recognize whether you have a
cable plugged in and "auto-mount" like a USB drive or something.
You seem to have some serious misunderstandings about how
these things are intended to work. I know of only a few machines
which treat ethernet cables as "hot pluggable". I'd be very
surprised to find that any version of Linux would do that.

Reconfiguring a live network is not something many OSs do. This
normally takes administrator intervention.

Mike
--
p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
This message made from 100% recycled bits.
I can explain it for you, but I can't understand it for you.
I speak only for myself, and I am unanimous in that!
Kevin J. Cummings
2005-07-09 01:43:13 UTC
Permalink
Post by THUFIR HAWAT
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...
looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>
arrakis eth0 123.12.23.43
arrakis eth0 192.168.1.1

would have suffuced....
Post by THUFIR HAWAT
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2
Connect arrakis eth1 and caladan eth0 to the hub only. If you've done
it right, you should be able to ping both machines from each other....
Post by THUFIR HAWAT
to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..
to do do that, is a default gateway required?
No, worry about the default gateway (and forwarding) after your local
subnet is working.
Post by THUFIR HAWAT
I'm just taking this one very small step at a time.
thanks,
Thufir
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
THUFIR HAWAT
2005-07-06 15:37:09 UTC
Permalink
On 7/6/05, Scot L. Harris <webid at cfl.rr.com> wrote:
...
Post by Scot L. Harris
The real question here is what are you trying to do?
...

looking at
<http://www.tldp.org/HOWTO/Masquerading-Simple-HOWTO/intro.html>

I've changed the IP addresses as follows:

arrakis eth0 123.12.23.43
arrakis eth1 192.168.0.1
caladan eth0 192.168.0.2

to be able connect arrakis eth0 to the hub, ping caladan, disconnect
arrakis eth0 from the hub, connect arrakis eth1 to the hub, ping
caladan, repeat..

to do do that, is a default gateway required?

I'm just taking this one very small step at a time.


thanks,

Thufir
Charles Heselton
2005-07-06 15:20:43 UTC
Permalink
-----Original Message-----
From: fedora-list-bounces at redhat.com
[mailto:fedora-list-bounces at redhat.com] On Behalf Of Ow Mun Heng
Sent: Wednesday, July 06, 2005 6:18 AM
To: For users of Fedora Core releases
Subject: Re: simple ping; pinging 101
...
[ big snip ]
The default route is to tell the interface which eth to send
the packets
to.
No matter how you set up the routing, the OS sees eth0 as the default
interface. If you want to specify that another interface is used to
send/receive the ICMP packets then try the "-I int" option:

'ping -I eth1 caladan' #from araakas

You could have both interfaces plugged in and enabled. But, as long
as eth1 is (pluggedin and enabled) this should work.

HTH

- -
Charles Heselton
charles.heselton <at> gmail <dot> com
CELL: 619-261-6866

PGP KEY:
5A27 58D2 C791 8769 D4A4 F316 7BF8 D1F6 4829 EDCF
Kevin J. Cummings
2005-07-09 01:39:08 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
Don't do this! It will give you more headaches than you want!

Use a *different* subnet for arrackis eth0. I suspect that the default
subnet for 192.168.0.0 network on arrakis is to use eth0, thus the
packets intended for caladan get sent on eth0.
Post by THUFIR HAWAT
caladan eth0 192.168.0.102
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
Two routes for 192.168.0.0 is not what you want to see. If you instead
replace the second route with one directly to caladan, it *might* work.

192.168.0.102 * 255.255.255.0 UH 0 0
0 eth1

You would need to add the route via:

route -add 192.168.0.102 eth0

As you can see, this is complicated. Instead, use a different subnet
for arrakis eth0 (like 192.168.1.0). Then configure arrakis to forward
packets from caladan to the arrakis eth0 network (by setting a gateway
on caladan and configuring IP forwarding on arrakis).
Post by THUFIR HAWAT
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
I'm sure that a traceroute will indicate that you're going out through
eth0 instead of eth1.
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
THUFIR HAWAT
2005-07-06 11:40:07 UTC
Permalink
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.

what's wrong with arrakis eth1, please?

I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.


arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102

terminal stuff from arrakis:

[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms

--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes

[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400

eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)

[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#

[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes

[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400

eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)

[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#


links:

arrakis mother board:
<http://www.ecsusa.com/downloads/manual_k7s.html>

eth1 NIC on arrakis:
<http://www.dlink.ca/product.php?PID=124>



thanks,

Thufir
Ow Mun Heng
2005-07-06 11:49:08 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
I seriously suspect it's a NIC issue. Dlink is using realtek 8139
driver yes? This one has cause me un-due pain.

To be sure.. switch the cables or switch the IPs (better)
Post by THUFIR HAWAT
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
Why is there no default route??
Lai Zit Seng
2005-07-06 12:01:23 UTC
Permalink
How are you selecting to ping via eth0 or eth1? It seems to be that in
both cases your ping would have chosen eth0. Yet the 2nd case fails.

Are you selectively pulling out physically the network cable to "select"
the network interface to use? This is not going to work!

Regards,

.lzs
--
http://zitseng.com/
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms
--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
<http://www.ecsusa.com/downloads/manual_k7s.html>
<http://www.dlink.ca/product.php?PID=124>
thanks,
Thufir
Jeff Vian
2005-07-06 12:31:53 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
Probably nothing is wrong except the configuration.

You have 2 NICs on the same subnet. Only one can be the default and in
most flavors of *nix when 2 NICs are on the same subnet the drivers
often get confused and in some cases all communication is either lost or
severely slowed down with this setup.

You can check which the system is using as the default by running
"netstat -r". The Iface column will tell which is the default interface
for the line that starts with default. Your route output below does not
list a default route, and it lists 2 routes to the 192.168.0.0 network.


A very simple test to see which interface is having the problem ( I
don't suspect either) would be to do the following

1. ifdown eth0
2. ping 192.168.0.102
3. ifup eth0
4. ifdown eth1
5. ping 192.168.0.102
6. ifup eth1
7. ping 192.168.0.102

then compare the results of the pings.

I suspect the only one that may have a problem is step 7 when both
interfaces are active.
Post by THUFIR HAWAT
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
caladan eth0 192.168.0.102
[root at arrakis init.d]# echo "arrakis eth0 pinging caladan eth0"
arrakis eth0 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
64 bytes from 192.168.0.102: icmp_seq=0 ttl=128 time=1.33 ms
64 bytes from 192.168.0.102: icmp_seq=1 ttl=128 time=0.465 ms
64 bytes from 192.168.0.102: icmp_seq=2 ttl=128 time=0.464 ms
64 bytes from 192.168.0.102: icmp_seq=3 ttl=128 time=0.472 ms
64 bytes from 192.168.0.102: icmp_seq=4 ttl=128 time=0.466 ms
--- 192.168.0.102 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4028ms
rtt min/avg/max/mdev = 0.464/0.641/1.339/0.349 ms, pipe 2
You do not know which interface this went through from this output
Post by THUFIR HAWAT
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
The only one showing a received count is eth0
Post by THUFIR HAWAT
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
No default route? It would have a UG flag
Post by THUFIR HAWAT
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
Now you have done a restart on both interfaces, and eth0 is not seeing
the other machine
Post by THUFIR HAWAT
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4900 (4.7 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:54 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3708 (3.6 KiB)
Interrupt:5 Base address:0xd000
eth0 still has the only received count. Eth1 has not received a single
packet.

Both show an increase in transmitted, but neither show a change in the
received from the earlier listing.
Post by THUFIR HAWAT
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:114 errors:0 dropped:0 overruns:0 frame:0
TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9200 (8.9 KiB) TX bytes:9200 (8.9 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
<http://www.ecsusa.com/downloads/manual_k7s.html>
<http://www.dlink.ca/product.php?PID=124>
thanks,
Thufir
Scot L. Harris
2005-07-06 15:10:05 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
The problem you are having is shown in the routing table above. Even
when you have one of the two network cables disconnected the routes are
still in the table for both NICs. Since both NICs are in the same
subnet they have routing entries to that subnet.

When you ping with eth0 connected it works. Then when you disconnect
eth0 and connect eth1 and ping it does not work. The reason is that the
ping looks in the routing table and finds the FIRST router to
192.168.0.0 network which is out eth0. But eth0 is not connected to
anything so it fails.

If you completely disable eth0 so that route is not in the route table
eth1 will work.

The real question here is what are you trying to do? Typically you can
not setup two NICs on the same LAN. The only way to do this is to bind
them together to act as a single interface. This will require a switch
that also understands how to bind interfaces/ports together.

You can setup each interface in its own subnet but you will have to have
other devices in the other subnet for it to communicate with.

The other thing that has already been pointed out is that you do not
have a default gateway. The default gateway is used for any packets
going to networks that are not on one of your local LANs. This default
gateway will go out one of the two interfaces not both.

Also note: the 169.254 address if from the zeroconf project and is
useless. This should be disabled by default but it is not. :)
--
Scot L. Harris
webid at cfl.rr.com

Things will be bright in P.M. A cop will shine a light in your face.
Charles Heselton
2005-07-06 15:20:43 UTC
Permalink
-----Original Message-----
From: fedora-list-bounces at redhat.com
[mailto:fedora-list-bounces at redhat.com] On Behalf Of Ow Mun Heng
Sent: Wednesday, July 06, 2005 6:18 AM
To: For users of Fedora Core releases
Subject: Re: simple ping; pinging 101
...
[ big snip ]
The default route is to tell the interface which eth to send
the packets
to.
No matter how you set up the routing, the OS sees eth0 as the default
interface. If you want to specify that another interface is used to
send/receive the ICMP packets then try the "-I int" option:

'ping -I eth1 caladan' #from araakas

You could have both interfaces plugged in and enabled. But, as long
as eth1 is (pluggedin and enabled) this should work.

HTH

- -
Charles Heselton
charles.heselton <at> gmail <dot> com
CELL: 619-261-6866

PGP KEY:
5A27 58D2 C791 8769 D4A4 F316 7BF8 D1F6 4829 EDCF
Kevin J. Cummings
2005-07-09 01:39:08 UTC
Permalink
Post by THUFIR HAWAT
two computers, arrakis and caladan, are
connected with some standard RJ45 Cat 5e cable
and a hub. arrakis can ping caladan from eth0.
arrakis cannot ping caladan from eth1.
what's wrong with arrakis eth1, please?
I'm 99.999% sure it's not a hardware problem.
eth0 is built-in to the motherboard,
eth1 is a D-Link NIC.
arrakis eth0 192.168.0.100
arrakis eth1 192.168.0.101
Don't do this! It will give you more headaches than you want!

Use a *different* subnet for arrackis eth0. I suspect that the default
subnet for 192.168.0.0 network on arrakis is to use eth0, thus the
packets intended for caladan get sent on eth0.
Post by THUFIR HAWAT
caladan eth0 192.168.0.102
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# built-in
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
#HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.100
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# D-Link System Inc RTL8139 Ethernet
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
HOSTNAME=arrakis
HWADDR=00:0D:88:37:FA:22
NETMASK=255.255.255.0
IPADDR=192.168.0.101
USERCTL=yes
PEERDNS=yes
TYPE=Ethernet
IPV6INIT=yes
[root at arrakis init.d]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0A:E6:A0:24:27
inet addr:192.168.0.100 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20a:e6ff:fea0:2427/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123 errors:6 dropped:0 overruns:0 frame:6
TX packets:62 errors:0 dropped:0 overruns:0 carrier:0
collisions:21 txqueuelen:1000
RX bytes:15378 (15.0 KiB) TX bytes:4144 (4.0 KiB)
Interrupt:5 Base address:0xd400
eth1 Link encap:Ethernet HWaddr 00:0D:88:37:FA:22
inet addr:192.168.0.101 Bcast:192.168.0.255
Mask:255.255.255.0
inet6 addr: fe80::20d:88ff:fe37:fa22/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:3090 (3.0 KiB)
Interrupt:5 Base address:0xd000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:108 errors:0 dropped:0 overruns:0 frame:0
TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8528 (8.3 KiB) TX bytes:8528 (8.3 KiB)
[root at arrakis init.d]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.0.0 * 255.255.255.0 U 0 0 0
eth0
192.168.0.0 * 255.255.255.0 U 0 0 0
eth1
Two routes for 192.168.0.0 is not what you want to see. If you instead
replace the second route with one directly to caladan, it *might* work.

192.168.0.102 * 255.255.255.0 UH 0 0
0 eth1

You would need to add the route via:

route -add 192.168.0.102 eth0

As you can see, this is complicated. Instead, use a different subnet
for arrakis eth0 (like 192.168.1.0). Then configure arrakis to forward
packets from caladan to the arrakis eth0 network (by setting a gateway
on caladan and configuring IP forwarding on arrakis).
Post by THUFIR HAWAT
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
[root at arrakis init.d]#
[root at arrakis init.d]# echo "arrakis eth1 pinging caladan eth0"
arrakis eth1 pinging caladan eth0
[root at arrakis init.d]# ./network restart
Shutting down interface eth0: [ OK ]
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Disabling IPv4 packet forwarding: [ OK ]
Setting network parameters: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
Bringing up interface eth1: [ OK ]
[root at arrakis init.d]# ping 192.168.0.102
PING 192.168.0.102 (192.168.0.102) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=2 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=5 Destination Host Unreachable
From 192.168.0.100 icmp_seq=6 Destination Host Unreachable
From 192.168.0.100 icmp_seq=7 Destination Host Unreachable
--- 192.168.0.102 ping statistics ---
8 packets transmitted, 0 received, +6 errors, 100% packet loss, time
6999ms
, pipe 4
I'm sure that a traceroute will indicate that you're going out through
eth0 instead of eth1.
--
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us
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