[CentOS] 2 network card setup

[Nicolas Thierry-Mieg]

Johan Vermeulen wrote:
> Dear all,
>
> I have a question regarding 2 network card setup, when e.g. using dhcp.
>
> Until a few months ago, I worked with OpenSuse. There in firewall
> config, you had to assign each NIC to a zone,
> either internal, external, DMZ or custom.
>
> Without it not much would work.
>
> I don't seen anything on CentOs in firewall config.
>
> So how does this work in CentOs?

maybe start by reading this:
http://lmgtfy.com/?q=iptables+%20site%3Aredhat.com&l=1