[LARTC] Several IP's, one mail and http server

[Aleksander]

Edmundo Carmona wrote:

>I don't know about the mail server, but apache supports virtual
>domains, and so the requests will be served differently depending on
>the request's domain, and not the IP of the host. A single IP should
>do the trick.
>
Yes, that's the case when the hostnames have the same IP. But when they 
have different ones and apache tries to answer their request, the 
clients will denied it, as it comes from a different IP.

Some ascii 'art' might help:

192.168.0.10 has external IP a.b.c.d (iptables SNAT)

a.b.c.d:80 DNAT \
                                    ---> 192.168.0.10:80
a.b.c.f:80  DNAT /

The request from the client arrives at apache and apache answers, no 
matter via which external IP it comes. But when the request comes via 
a.b.c.f, then the client will be expecting the answer form a.b.c.f, not 
a.b.c.d, where it will come from. Apache is assigned a.b.c.d and has no 
way of changing that, actually apache thinks it sending from 
192.168.0.10 anyway.

The only solution I see is having a (virtual) interface for each 
external IP. That so?