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I have two NIC Ethernet card (eth1 and eth2) on the same computer (linux) connected by a cross cable.

The two interfaces are on the same subnet :

eth1 : 

eth2 : 

Then i add a route for each interface :

route add -net netmask eth1 

route add -net netmask eth2

Finally,i'm trying to ping :

ping -I eth2 or ping -I eth1

Ping command reaches error : Destination Host Unreachable

Can anyone help me to fix this issue?

Thank you.

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migrated from Jul 6 '11 at 14:22

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Have you tried adding -r to the ping command? – ezpz Jul 6 '11 at 10:28
Are the interfaces UP? – Keith Jul 6 '11 at 11:24
Yes both interface are up and i also try option -r on the ping command.But unfortunately ping reach same error. – Monu Jul 6 '11 at 11:56
Why did you specify a route? Are you using a subnet that is configured elsewhere within your network? – cwawak Jul 6 '11 at 14:33
Did you run the route commands as root? Are those ping commands separate, as in, ping -I eth2, then you ran ping -I eth1, not ping -I eth2 or ping -I eth1? Try running ping like this ping -I eth1 – evan.bovie Jul 6 '11 at 14:33
up vote 1 down vote accepted

To fix this issue, i use two virtual machine. And i can ping eth1 or eth2, with eth2 or eth1.

Thank you,all for yours comments and help.

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Basically when u ping from your system, the source IP is set to INADDR_ANY. And when the kernel finds the destination IP to be on the same system, it will simply loopback it. Its using loopback (lo) interface.

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