topic Re: NAT outbound SMTP in Network Security

NAT outbound SMTP

zulu-5-2010 — Mon, 11 Mar 2019 17:40:29 GMT

Ladies and Gents,

I have 3 interfaces in my PIX, Inside, Public and DMZ. I have a host (192.168.1.111) in the DMZ that needs to relay mail to a smart host on the internet. However, the smart host only accepts connections from certain addresses. Public interface's address is one of them. So I've set up an ACL, applied it to the interface.

access-list DMZ_access_in extended permit tcp host 192.168.1.111 eq smtp object-group smarthostcluster eq smtp

access-group DMZ_access_in in interface DMZ

Now I have to NAT/PAT the traffic, since the smart host only accepts connections from the Public interface.

global (Public) 1 interface

nat (DMZ) 1 192.168.1.111 255.255.255.255

However, it still doesn't work. It says connection is refused. So, I wonder if I have missed something. Our main server sends out fine, but the Inside ACL is a lot less restrictive so I really don't know who's at fault, me or the smart host.

Regards

Igs

Re: NAT outbound SMTP

bhisham84 — Tue, 04 May 2010 06:50:55 GMT

access-list DMZ_access_in extended permit tcp host 192.168.1.111 object-group smarthostcluster eq smtp

access-group DMZ_access_in in interface DMZ

Now I have to NAT/PAT the traffic, since the smart host only accepts connections from the Public interface.

global (Public) 1 interface

nat (DMZ) 1 192.168.1.111 255.255.255.255

Try this hope this will work...!

Thanks/Bhisham

Re: NAT outbound SMTP

zulu-5-2010 — Tue, 04 May 2010 06:55:39 GMT

Bhisham, thank you for your help. Greatly appriciated.

I'll change the line tomorrow, see what happens

Re: NAT outbound SMTP

zulu-5-2010 — Thu, 06 May 2010 23:24:59 GMT

It worked.

thank you Bhisham