Kees Theunissen wrote:
> alex49201 wrote:
>> random high port? I'm trying create a firewall rule, that would limit
>> any mail leaving the server unless it was sent through sendmail. (as
>> opposed to a local user setting up their own smtp server in their pine
>> or something)
[ ...]
> What prevents you to only allow your mail server(s) to setup a TCP
> connections to a remote port 25? You only have to filter on local
> IP number and remote port 25.
> Filtering on local port 25 would be useless anyway. It doesn't
> distinguish between your mail servers and other systems that are
> running some kind of a MTA.

Sorry about this answer.
I didn't read your question with enough care, and supposed you were
configuring an external firewall.

Regards,

Kees.

--
Kees Theunissen.