The other problem this spamming practice creates is that the spam looks like it originates from a domain not involved in spamming in any way. This results in spam complaints against innocent parties and can create a great deal of trouble for the owners of the faked domain names.

While there is no way to stop a spammer from forging a domain name in the headers, letting people know what is happening can minimise the damage if that is happening. You will want to do the following:

• Prepare a form email explaining that this spam is using a forged header and you are an innocent bystander, send that to anybody who complains to you.
• Post that email on usenet in news.admin.net-abuse.sightings.email.
• Also post it to the SPAM-L mailing list see:

http://www.claws-and-paws.com/spam-l/
(read the FAQ for posting guidelines first)