Thanks for the explaination Sven.
I have tried altering my from address in Pine 4.44, under
SuSE 8.1 pro.
When I try to send the mail to suse-security@suse.com with a
dummy from address in the header from, Pine gives me the
following error message:
Mail not sent:
To: suse-security@suse.com From: Sven Wahl
Subject: Re: [suse-security] Curious response
snip
A2. The header from is probably what you think of as the "from"; e.g. From: foo@bar.com It is contained in DATA portion of the mail (that's the part of the mail that you, as a user, write). The envelope from is written by your mail transport agent, or MTA. That's the thing that your mail client hands the message you just wrote off to to have it delivered. An envelope is generally represented as this in the traditional mbox format: From foo@bar.com Fri Mar 1 12:59:36 2002 If you use maildirs or some other mailbox format you probably won't have that. Most MTAs copy the envelope from to the Return-Path header so you can also get it from that. This is who your MTA, in the words of RFC 822bis, says "the author(s) of the message, that is, the mailbox(es) of the person(s) or system(s) responsible for the writing of the message.'' The mailing list software we use (ezmlm+idx) takes the envelope from as the address to subscribe when you email LISTNAME-subscribe@suse.com. Other mailing list software might use the header from.
There are lots of good technical reasons why the envelope from is used (which you can read all about at the author's site: http://cr.yp.to/immhf.html) but a big benefit for you is that since the envelope from isn't displayed in list postings and the header from is ignored you can set your header from to be whatever you want. This means that you can use your main email address for the list and, if you munge the address, you won't need to worry about it being harvested by an an evil spammer. In other words, you are encouraged rot13, reverse, encrypt, or do whatever to your header from (*except* leave it unqualified) and it won't affect your subscription at all.