Making users to use port 587 for submission emails

[Paul Howarth]

On Sat, 2005-09-10 at 11:48 +0200, Sasa Stupar wrote:
> Hi!
> 
> I am running Sendmail 8.13.4 on FC4 with cyrus2. I have configured sendmail 
> to listen on ports 25 and 587. Since all of the client mail software use 
> port 25 by default instead of 587, how do I make users to use 587 and deny 
> access to 25? Something like: when they try to connect to port 25, they get 
> back error - you are not a server so you must use port 587.

Where are these users located?

You can turn off relaying for everywhere except localhost, which will
give any non-local clients a "relaying denied" error; using port 587
they will need to authenticate and that will override the relay check.

You can't easily tell the different between an MUA and an MTA connecting
to your port 25 - they are both acting as SMTP clients. This is why port
25 blocking became necessary in the first place.

Paul.
-- 
Paul Howarth <paul at city-fan.org>