Varnish and multiple interfaces

[Mattias Geniar]

> According to tcpdump, traffic from varnish is coming from eth0
(incorrect IP)
> and traffic coming from nginx is coming from eth0:0 (correct IP).
Apache logs
> are also confirming the IP information.

That's possible, if both eth0 and eth0:0 are in different subnets. If
your backend for nginx is in the same subnet as eth0:0 but in a
different subnet as eth0, it'll go via the eth0:0 alias.

So my guess would be that your varnish backend is in a different subnet
than your eth0:0 so it takes the default route via eth0?

Regards,
Mattias