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I am running Red Hat 7.1 on my current firewall.  I have two ethernet cards: eth0 and eth1.  Is there a way to set up my server to forward mail that arrives only on eth1 (inside link) while blocking all forwarding requests coming from eth0?

I've read some of the man pages and looked through my "Linux Bible" book but I can't find any instructions on how to set this up - just information on why I shouldn't do this.

Any thoughts, pointers, or suggestions?

Any help would be greatly appreciated.

Thanks!

Greg