I got a bounce message from mail addressed to a person who had not worked
here since 1991. I had not seen this particular type of header from
----- Message header follows -----
Received: by tymix.Tymnet.COM (4.1/SMI-4.1)
id AA21511; Thu, 3 Apr 97 20:06:27 PST
Received: from 184.108.40.206
by tymix.Tymnet.COM (in.smtpd); 3 Apr 0 20:06:27 PDT
Received: from Cyber Promotions' new "ISPam Network" - Details
X-Shocking-Web-Page: Visit http://www.cyberpromo.com
X-Please-Note: THIS SERVER RELAYS MAIL FROM OTHER SOURCES ONLY!
Comments: Authenticated sender is <firstname.lastname@example.org>
Received: from savetrees.com (savetrees.com [000.000.000.000]) by savetrees.com (0.0.0./0.0.0.) with SMTP id AAA000000 for <email@example.com>; Thu, 3 Apr 1997 19:26:23 -0500 (EST)
----- Message header ends -----
Note the "Date:" and "X-" headers.