rhas3 (taroon2) eth0 eth1 network looks active, but does not send/rec

[Steve Phillips]

On Tue, 4 Jan 2005, Roland Wong wrote:

> update:  I attached the crossover cable from eth0 to eth1 on the server, 
> set eth0 to 10.0.0.101, and eth1 to 10.0.0.102.  then I pinged eth1 from 
> eth0

This may create internal confusion (actually, seeing as its not working it 
will create internal confusion)

> # ping -Ieth0 10.0.0.102

Meaning that this wont work..

> I got error msgs saying the destination host is unreachable.  I'd been 
> running tcpdump on another terminal, and tcpdump returned this:

yup, because it probably cant find the other interface..

> 13:16:53.931306 arp who-has 10.0.0.102 tell server
> 
> again, any help is appreciated.  I will post more symptoms and other 
> fixes I've tried.

Basically, you cant have two seperate physical interfaces on the same 
subnet and expect things to work properly, things get terribly confused 
and the box wont know what interface to respond with when it gets traffic 
to/from these interfaces.

the way you would have multiple IP's on a single subnet is to use ip 
aliases (eth0:1, eth0:2 etc etc)

(Note: just having the interface ip's setup on the same subnet will 
probably cause this problem, no need for cables to be plugged in at all. 
try unsetting eth1's ip address and repeat your crossover test..)

-- 
Steve.