Dear All,

We use Fetchmail to a POP3 mail box of our internet service provider to get mail of my office. Then we distribute them by a Sendmail server to each user through a LAN.

We received complaints that we are sending out spam mails. I suspected that the spam mails are generated by bouncing mails to users unknown to our office. This is because most of the spam mail we received are of fake senders and our servers bounce messages to them. Generating a lot of unnecessary traffic.

Are the returning messages of unknown receiving users being send out by Sendmail or Fetchmail? Could we stop the server sending out returning mails? How?

Please help.
Regards,
Anthony Pong

What do you mean by
Could you show us a sample of what you are calling a spam?


Anyhow, You could restrict access to sendmail to the localhost only as you don't seem to be using it for other purposes.

well listen to me. I am giving you a perfect idea here.

I think you should tell sendmail to accept all emails that are destined to your domain but the user is unknown.

For example

By default when your sendmail receive message for non-existent-user@YOUR-DOMAIN.COM then it says. Wellll the domain is sure mine and i accept messages for it but i don't know if "non-existent-user" exist on this server. So then sendmail bounces that message back to sender.

So what i am saying is that you need to make sendmail accept messages even if the user doesn't exist on your server, and then send those unknown user's emails to an account on your server named (lets say) "junkcatcher".
And then just write a simple bash script and run it every hour through cron job to delete all mails for "junkcatcher" user... HOWS THAT SOUND ???

ok now let me tell you how to achieve this goal

first in /etc/mail/sendmail.mc file put following

then after making sendmail.mc file. Restart sendmail

Thats it. Hope it helps you.

and yeah offcourse you need to make junkcatcher account first.

thats it ...

else if you can't do it
contact me http://kingkashif.com

wooooo let me go to sleep now it's 4:45 AM

You should test your email server to see if it's properly setup.

Go here http://www.spamhelp.org/shopenrelay/ to test it.

From http://en.wikipedia.org/wiki/Backscatter_(e-mail):
OP gave a very understandable description of a well known problem.

Or they may simply and inadvertently have been running an open relay. Also a common and well known problem. If the OP had replied to WebDevil, we would have been able to take it further.

Hello buddy,

Can I achieve the same goal on postfix?

Rdgards..