Weird network problem

[Barry Brimer]

> Hi,
>
> I have a little problem: a machine is configured with two ip addrs on 
> the same eth if, the other being an alias. When connecting to the 
> primary addr, even when pinging it, the response seems to come from the 
> alias addr; this of course messes up the config of the firewall sitting 
> between the server and clients. How is it possible? Why is the kernel 
> answering on the alias? How can I force it to answer with the correct 
> address?

Sounds strange.  Do you have any iptables rules that would explain this .. 
most likely in the 'nat' table?

'iptables -t nat -L -n' will tell you.

I suppose you could use an iptables rule 
to force traffic out that IP address .. something like:

iptables -t nat -I POSTROUTING -s <ip address of eth0:0> -j SNAT 
--to-source <ip address of eth0>

(This should all be on one line, regardless of how it appears in this 
message).

Barry