Hi,

I configured ( sendmail + Smarthost + pop-before-smtp settings + smtp auth settigns ), today i saw 18000 mail in mailq and somebody sending mail from my mailserver ,as i got reported by ISP for spaming. How someone broke the sendmail + pop-before-smtp settings. i usually access that system through webmin. Is webmin cause to hack password.

Or How someone break sendmail security without even choosing my own user / password spamper settings messages to smart hosts to yahoo / gmail with his own junk user name and password?

I stopped sendmail for the time being.
Any idea what i should look for and what i should go for its remediation?

Any help would be greatly appreicated.

Usually it means you've setup your sendmail as an open relay and they simply relayed through you.

I'd suggest you do a Google search for "securing sendmail". You'll see a lot of information out there including this link:
http://www.enterprisenetworkingplane...le.php/1382251

Webmin is unsafe to start with, in my opinion. If you want a secure system, run as few open services on it as you can. Disable EVERYTHING that's not needed. On my mail servers, all I've got running is sendmail and SSH...you should be easily able to configure and maintain sendmail via a terminal window.

And as jlightner said, you've probably got an open relay running. Set up a good ACL, and turn off open relays.

Thaks for all reply , i am checknig back my sendmail settings and hopefully would resolve this issue.

Thanks