spoofed emails and the problems from it

[cosanostra]

I've recently had experiences of emails from a restricted group on googlegroups being replicated elsewhere on a googlegroup and causing a load of problems.

they came from one of the list member's email address and appear to have been posted by someone else using the list member's email address.

I have a very limited knowledge of emailing and the message source details but it has been pointed out to me that the X-IP is the same in other messages.

Can the X-IP be forged?

thanks very much

c-n