openemm internal mail server is open relay

novad · Post by **novad** » Thu Nov 19, 2009 6:03 pm

Hello everybody,

I have configured an openemm server that works really good but choosed NOT to use sendmail (several good reasons for that).

I'm quiet happy with the integrated mailserver BUT I saw that it is an open relay (That's really bad).

Is there a way to disable that... I really tried to find how but had no success with that). Please don't just tell me to read the installer guide (i did)... If the answer is in there please tell me which part I missed

Thank you for your help

Novad

P.S: Sorry for my english... My german or french is much better

Post by **maschoff** » Fri Nov 20, 2009 8:40 am

Why do you think that the internal SMTP server of OpenEMM is an open relay?

novad · Post by **novad** » Fri Nov 20, 2009 9:05 am

Hi,

I've an account at the website dnsstuff.com.

On this site there is a test that you can use to test your "domain". It tests a lot of things and one of these things is if the mail server(s) is(are) open relay (I often use it).

And the test says that the server allows relaying. In fact they specifically test relaying to their domain to say that.

If you want I can also test it with a simple telnet connection

Regards,

Novad

novad · Post by **novad** » Fri Nov 20, 2009 9:28 am

Hi (again)

I just tested relaying with telnet and in fact the mail wasn't sent....

What happens is that the server "accepts" the request for sending the mail for an external domain but finally never sends it.

That's also why a lot of "open relay tests" states that the server is open relay (even if it's not in the end)

The way the mail server "should act" is to answer "relay access denied" on the command "RCPT TO:" when the mail domain is not the one from the sending system.

Is there a way to do that???

Best regards,

Novad

Post by **maschoff** » Fri Nov 20, 2009 10:12 am

That would require a bigger change in the code and has a low priority for us (since the internal SMTP server is *not* an open relay).

However, we would gladly accept a patch contribution from your side and integrate it in the mainline.

novad · Post by **novad** » Fri Nov 20, 2009 3:33 pm

I would love to do it but I have no programming skills

I made a special smtp proxy rule for openemm on our firewall and that made the trick too.

Thank you for your answers.

Novad