dual ethernet ports problem.

dual ethernet ports problem.

[Adarsh Daheriya]

hi all,

i have got a system which has 2 eth ports. i use one of them (eth0) to 
"network boot" the system
using dhcp, tftp and then mount the nfs file system on it.

this leaves the other port (eth1) unusable. i cannot ping to the other 
system through it.
but when i ping any of the two eth ports from some other system i get 
the reply back.
but to my amazement the mac entries of both the ports is that of eth0 in 
arp table. (arp command)

why and how eth0 is acting as a proxy (perhaps) for both the ports and 
how can i disable it?

could anybody please help me in this concern.

regards,
-adarsh.

Re: dual ethernet ports problem.

[Eli Carter]

Adarsh Daheriya wrote:
> hi all,
> 
> i have got a system which has 2 eth ports. i use one of them (eth0) to 
> "network boot" the system
> using dhcp, tftp and then mount the nfs file system on it.
> 
> this leaves the other port (eth1) unusable. i cannot ping to the other 
> system through it.
> but when i ping any of the two eth ports from some other system i get 
> the reply back.
> but to my amazement the mac entries of both the ports is that of eth0 in 
> arp table. (arp command)
> 
> why and how eth0 is acting as a proxy (perhaps) for both the ports and 
> how can i disable it?
> 
> could anybody please help me in this concern.

Both ports on the same subnet/switch/etc perchance?

Linux replies to an IP address out of any port it cares to.[1]  I've 
seen this come up a number of times, but I can't seem to find references 
to it in google.... Ah, wait, try this:
http://www.cs.helsinki.fi/linux/linux-kernel/2002-16/0676.html
LWN writeup about this: http://lwn.net/Articles/45373/
(Google for 'linux-kernel ping route IP MAC wrong' w/o quotes.)

HTH,

Eli

[1] Over-simplification to the extreme, and probably wrong to boot. 8)
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