How to Accept SMTP Requests for Subnet Only

nytcrwlr70 · 07-02-2007, 04:39 PM

Hello,

how do I allow ip addresses for subnet 192.165.x.x to access my server via SMTP but any other subnet outside of that group is rejected?

I tried the following syntax:

iptables -I INPUT 1 -s 192.165.0.0/16 -d 192.165.17.3 -p tcp --dport 25 --tcp-flags SYN,RST,ACK SYN -j ACCEPT

iptables -A INPUT -d 192.168.17.3 -j REJECT

Will this work?

coolb · 07-05-2007, 07:30 AM

what about hosts.allow and hosts.deny ?

TigerOC · 07-06-2007, 06:21 AM

This kind of restriction should be part of your MTA (Postfix certainly is able to define the network connection).

nytcrwlr70 · 07-06-2007, 09:58 AM

This is true. However, I want Postfix to drop e-mail from the outside world and only allow connections from within out internal network. Perhaps I'll take this to a Postfix forum.

TigerOC · 07-07-2007, 01:21 AM

Quote:

Originally Posted by nytcrwlr70

This is true. However, I want Postfix to drop e-mail from the outside world and only allow connections from within out internal network. Perhaps I'll take this to a Postfix forum.

The easiest way to deal with this is not to forward port 25 on your external router interface. If the interface is closed then there is no connection to the outside world.