Mailinglist Archive

Understanding E-mail Spoofing
by Deb Shinder - WindowSecurity.com - Monday, 25 October 2004.

If you receive a snail mail letter, you look to the return address in
the top left corner as an indicator of where it originated. However, the
sender could write any name and address there; you have no assurance
that the letter really is from that person and address. E-mail messages
contain return addresses, too – but they can likewise be deliberately
misleading, or “spoofed.” 

http://www.net-security.org/article.php?id=737