how to prevent spamming using your domains

I have seen many emails sending out using one of our domains. We are sure we do not send them. Checking the headers, and seeing they have been sent from many other servers.

I assume that there is software searching domain names on the internet, then sending emails with founded domains? In that case, I doubt there is a method to prevent, but still wonder if someone can suggest any idea?

thanks,

You can only stop emails if they come from your server. If other systems are sending out emails with your domain spoofed in the HELO handshake in the SMTP delivery there's nothing you can do about it.


If your from address is spoofed in spam not coming from your server there's nothing you can do about it except try and find the spammer responsible, and then perhaps sue them if you can.

Usually that happens when someone's desktop system is compromised. The compromised system will use one of the email addresses in its addressbook as the sender of the spam.

So your domain gets spoofed.

It's been a problem for us as we were recently blocked because our name was found in spam. Note that our servers had nothing to do with it, and we've never ordered any spam sent out, no less with our domain name in it.

Generally the people doing the blocking based on spoofing know the limitations of their systems and will unblock you if they have, and if you let them know the circumstances.

But don't even try if it really is your spam, as they'll figure it out soon enough, and escalate the blocks.

Jeff