Re: [cobalt-developers] cobalt sendmail tricks/open relay

[Michael Stauber <devel@xxxxxxxxxxxxxx>]

> My ISP just fingered me as an open relay.  I'm not really happy about
> this. I've done research on sendmail in general, and have noticed
> that Cobalt has a really insecure version of sendmail running - 8.10.2

That's what POP-before-SMTP (or the so called "POP authenticated Relaying") is 
for. You can activate it in the "Advanced" tab of your Sendmail configuration 
in the GUI.

Once POP-before-SMTP is enabled people can only relay email through your 
server if they authenticate themselves through POP3 or IMAP first.

So once a user checks his email his IP address is temporary allowed to send 
email through your server.

More information about how to counter SPAM and unwanted relaying can be found 
here in the article "SPAM prevention: POP-before-SMTP and related questions" 
at this URL:

http://www.solarspeed.net/kb/659.php

-- 

With best regards,

Michael Stauber