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To: drums@CS.UTK.EDU
From: "Roger Fajman" <RAF@CU.NIH.GOV>
Date:     Tue, 03 Oct 1995  22:47:52 EDT
Subject:  Re:  What's the Sender header for?

> (1) Some mailing list software uses Sender for the name of the list or
> the list-request mailbox.  This has the utility of answering the
> question "why did I receive this message".  The To header may not be
> sufficient for that since it may contain multiple list addresses.
> LISTSERV is not the only MLM that uses Sender.  Listproc puts the
> listname-request address into Sender.

I looked through about 250 messages I received since noon and saw
Listproc also putting the address for bounces, a back-level Listproc
putting in the list address, and majordomo putting in either the
-request address or the address for bounces, depending on the list.

> (2) Some user agents allow the user to sent the From field to whatever
> they want.  This is useful when the address that one wishes people to
> use is one that goes through a forwarder (e.g., fajman@nih.gov). The
> utility of the Sender field in this context is that is can be used to
> indicate where the message really came from, so as to discourage
> forgery.

I saw two messages from the same person that seemed to have this.  She
seemed to be using Netmanage Chaneleon.  Of course, they may have been
others that were masked by MLMs using the Sender header.