Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site hou3c.UUCP Path: utzoo!watmath!clyde!burl!hou3c!smb@ulysses.UUCP From: smb@ulysses.UUCP (Steven Bellovin) Newsgroups: net.mail.headers Subject: Re: What are SMTP commands "EXPN" and "VRFY" good for? Message-ID: <8409160205.AA15551@kalypso.UUCP> Date: Sat, 15-Sep-84 22:05:49 EDT Article-I.D.: hou3c.832 Posted: Sat Sep 15 22:05:49 1984 Date-Received: Thu, 4-Oct-84 02:45:23 EDT Sender: ka@hou3c.UUCP (Kenneth Almquist) Lines: 16 To: header-people@mit-mc.ARPA, wales@ucla-locus.ARPA Except for the problem of failed mail in a list expansion -- on which matter I agree with Rich Wales -- EXPN struck me as a good idea for handling mail to multiple lists, or to a person and a list. As is, Rich is going to receive two copies of this letter -- one direct, and one via the list expansion. A sufficiently smart mailer could use EXPN to discover that Rich is on the list, and not send him a separate copy. (We'll ignore the fact that this particular note is going via uucp to an SMTP host; it wouldn't really change anything if it weren't.) --Steve Bellovin AT&T Bell Laboratories ulysses!smb@berkeley.arpa smb.ulysses.btl@csnet-relay (should work, but probably doesn't) smb.research.btl@csnet-relay (works more often)