firewall settings to protect mail server

Oct 02, 2008 4 Replies
T

my router = Cisco 2651XM with wic-adsl card. IOS = c2600-adventerprisek9-mz.124-2.T.bin



I've set up a mail server computer at my home and I was wondering if there are any good known router firewall settings that will hinder spammers relaying junk mail through my mail server. I know there are several things I can do on the server machine itself, but I'd also like to stop spammers at the router if that's possible. I know I can filter traffic based on outside IP addresses but people's ip addresses change all the time so that's not a viable approach. Is it possible to filter outside traffic based on a mac address? Thanks for any advice.


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D

The router/firewall usually doesn't have the processing time to do many of the lookups required. It really is better at the app level.

Single best thing you can do low-level is probably setup an RBL to block IPs against zen.spamhaus.org. I'm amazed at what that will stop in our network.

But routers can't do RBL lookups and block on that.

SPAM requires full TCP connectivity, so it has to be a real live IP, and SPAMers typically bounce their junk off owned machines around the world, so if you block them at the router, you probably will block people trying to get to your webserer (if you have one), even if their machines are sending out SPAM mail without their knowledge.

Umm, what would MAC address filtering get you with SPAMers? It's not possible, they only exist layer-2 on the same network.

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G

well maybe you are trying to stop spammers on the same subnet as your mail server ^^

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G

You dont see any other, than your own MAC addresses on the same subnet as your mailserver.

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