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From: coolidge@brutus.cs.uiuc.edu (John Coolidge)
Newsgroups: news.software.b
Subject: Re: Anyone interested in end-to-end checksums in news?
Summary: Not so sure...
Message-ID: <1989Nov17.001345.16022@brutus.cs.uiuc.edu>
Date: 17 Nov 89 00:13:45 GMT
References: <1989Nov16.173546.6101@brutus.cs.uiuc.edu> <14596@well.UUCP>
Sender: news@brutus.cs.uiuc.edu
Reply-To: coolidge@cs.uiuc.edu
Organization: U of Illinois, CS Dept., Systems Research Group
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jef@well.UUCP (Jef Poskanzer) writes:

>In the referenced message, coolidge@cs.uiuc.edu wrote:
>}                                  Message-id's seem to be the most
>}common thing to get mashed in transmission.

>Uh, doesn't this seem a little unlikely to you?  Doesn't it seem more
>likely that bits all over the articles are getting munged with equal
>probability, but we tend to notice when it happens to Message-Id's
>since that results in duplicate articles?

Hmm. I've seen plenty of articles with munged Message-id's, and
many of those had munged text too. I don't remember ever seeing
an article with munged text in which the Message-id _wasn't_
munged, though. This is probably because, if the text gets mashed
but the Message-id doesn't, then downstream feeds don't take the
mashed copy but only the good one (all of the duplicate, mashed
Message-id postings I've seen seem to have been sent twice by the
originating site...).

This might imply that checksumming Message-id, while not sufficient
to stop all body-munging, will have the effect of stopping lots of
it by halting propagation. In any case, checksumming all possible
header fields and the entire text is the right thing to do anyway.

--John

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John L. Coolidge     Internet:coolidge@cs.uiuc.edu   UUCP:uiucdcs!coolidge
Of course I don't speak for the U of I (or anyone else except myself)
Copyright 1989 John L. Coolidge. Copying allowed if (and only if) attributed.
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