How can I Block port 25

[zodell]

I want to block all smtp traffic from my customers except for packets destined for my mail server and my mail server only. I would like to do this at the edge and not at the core. I put in the following ACL, but it blocked all smtp traffic.

access-list 115 permit tcp any eq smtp 192.168.0.0 0.0.0.255

access-list 115 deny tcp any eq smtp any

access-list 115 permit ip any any

The reason that I want to do this is to cut down on spam reports to my upstream provider.

Any help would be appreciated.

[peterledwidge]

access-list 110 permit tcp [customer subnet] [mask] host [your mail server] any eq smtp

access-list 110 deny tcp any any eq smtp

access-list 110 permit ip any any

example

access-list 110 permit tcp 192.168.0.0 0.0.0.255 host 172.160.1 eq smtp

Ensure you apply the rule in the proper direction.

HTH

[tstrosnider]

This is what I am running on my pix

access-list inside_access_out permit tcp host any eq smtp

access-list inside_access_out deny tcp any any eq smtp

Pretty much what it does is it blocks all mail outbout to the internet except from the mail server. I use this rule to deny any virus outbreak that installs a local mail engine and spams away, this way it will show up on my syslog, and I know immediately which workstation is infected. And no mail is sent out of the network unless it goes through the allowed ip.

Hope this helps.

Trevor