question about using iptables.

People:
I´m new using iptables and i want to know if it is possible
to forward all the packages to a specific port to a specifica ip address. This is my environment and what i need to do:

I have a lan under 190.168.0.x

then a have a gateway with iptables + ipcop to filter all packages to WAN (internet)

My ISP give us a set o public ips and all the packages from the lan to the wan use one public ip (one from that set) = 190..139.106.194

Currently our smtp server is been considered as SPAM for a few domains (and we need to change this ASAP).

It is poosible to configure iptables to set all the packages from 190.168.0.x:25 (smtp port) to use a different public ip addres of the set that our isp gives us?

brieflly:

all packages from our lan to a port different to 25 use 190..139.106.194 and all packages from our lan to port 25 use 190.139.106.195

Thanks in advance!

Nico

Hi,

Nicolas Grossi írta:

I would use a smart host (the smtp gateway of your ISP)

Swifty