Well, it does seem more practical than TCP over SMTP:
http://www.detached.net/mailtunnel/ ("ping replies up to an hour, maybe
<Robert.Herriot@pahv. To: Carl Kugler/Boulder/IBM@IBMUS, email@example.com
Subject: RE: IPP> rfc3093 - Firewall Enhancement Protocol (FEP)
04/16/2001 06:25 PM
RFC 3093 is interesting reading.
Did you notice that its publication date is the same as RFC 3092 'Etymology
of "Foo"' -- namely April 1, 2001?
This might be useful for INDP through firewalls.
This archive was generated by hypermail 2b29 : Thu Apr 19 2001 - 18:51:33 EDT