On Wed, 17 Nov 1993, John Arnfield <[log in to unmask]> wrote: > I run a list (CLIMLIST) for people working in climatology and related > disciplines. It is moderated and only the list owner (me) can send to the > list. CLIMLIST is run from LISTSERV@PSUVM (aka [log in to unmask]). > I distribute to it by email from Ohio State (magnus.acs.ohio-state.edu). > > I was very surprised on Monday when an item was distributed to the > list which I had not sent. It was a copy of last week's Digest and the > 'Original sender' warning identified the sender as a CLIMLIST > subscriber in Manitoba who had elected to receive the list in Digest form. > My questions (after this long-winded preamble) are as follows. > (1) Why might the mail have been sent back to CLIMLIST@PSUVM? This "reposting" has happened to me, too, on a moderated list. Some mail-agents support a 'bounce' command, which sends the E-mail to any address. For example, here's the headers of one such message, which I sent from my account on SOL.UVIC.CA to my account on UVVM.UVIC.CA (I've "anonymized" [sic] some of the fields): ! Return-Path: <@UVVM.UVIC.CA:[log in to unmask]> ! Return-Path: <[log in to unmask]> ! Received: from johnny.u.washington.edu by sol.UVic.CA ! Received: by johnny.u.washington.edu ! X-Sender: [log in to unmask] ! Date: Wed, 17 Nov 1993 19:37:36 -0800 (PST) ! From: USER NAME <[log in to unmask]> ! Subject: Re: YOUR QUESTION ! To: Melvin Klassen <[log in to unmask]> ! In-Reply-To: <[log in to unmask]> ! Message-Id: <[log in to unmask]> ! Sender: [log in to unmask] Note that the 'From:' line is still the original. If I had "bounced" the E-mail to 'LSTOWN-L@SEARN', LISTSERV would have ignored the 'Sender:', 'X-Sender:', and 'To:' tags, and would have posted the message to the LSTOWN-L list! The message would have appeared to have been posted by 'USERNAME'! > (2) Even if this did happen, why did LISTSERV then distribute it > to the list given that CLIMLIST is moderated? Because the 'From:' line is the original, LISTSERV has verified that the ID in that line *is* one of the "editor" IDs for the list. Also, since it was a week old, LISTSERV didn't recognize the text as a "duplicate" posting (the cache of previous-postings isn't infinitely big), so, LISTSERV didn't reject it for that reason. > With respect to (2), I am frequently contacted by people wanting to send to > the list who have had their postings rejected as 'unauthorized', so I know > that, in general, the restriction on sending works. I guess the mail must > have looked as though it came from me to LISTSERV. Exactly.