2 Replies Latest reply on Sep 5, 2013 1:04 PM by noor

    Block outgoing port 25 for all but server?

    maxpower New Member

      I've been searching and can't find an answer to this question: I would like to block all outgoing port 25 traffic except for my email server on a NetVanta 1335 with firmware R10.1.0.E. After much research and looking through the NetVanta I'm just not sure how to accomplish this. Any advice would be greatly appreciated.



        • Re: Block outgoing port 25 for all but server?
          jayh Hall_of_Fame

          Exact details depend on whether you are using NAT or not. Access-list on Private side should look something like this:


          Assume your mail server is


          ip access-list extended inside-to-public

            permit ip host any

            deny tcp any any eq 25

            ! Any other outbound restrictions here

            permit ip any any


          Then apply this ACL to your outbound policy-class on the LAN side facing the public, something like...


          ip policy-class Private

            nat source list inside-to-public interface [interface name here] overload

          Of course you'll need the appropriate reciprocal port-forwarding to allow inbound mail from the public to your mail server as well. Post your existing config if this doesn't help.

          • Re: Block outgoing port 25 for all but server?

            maxpower -

            I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post to unmark it and select another in its place with the applicable buttons.  If you have any additional information on this that others may benefit from, please come back to this post to provide an update.  If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.