Is there any detailed information about the CRC mechanism for loop checking?
I'm interested in knowing the probability of an accidental match, and the
retention time of CRCs being matched against new messages for duplicate
detection.

This probably calls for some background: I manage lists for an IEEE
standards working group. Drafts of standards under development are submitted
periodically to the membership for voting and comment. We ask that responses
be returned to a designated list, with a subject line identifying the draft
and the vote. There's a ballot-response form, too, but if the vote is
Approve without any comments, it doesn't collect any more information than
is on the Subject and From lines of the mail header.

One subscriber decided that meant he could send his vote with no message
body. That worked--the first time. The second time (a day later, on a
different draft standard), the no-body matched the CRC of the first one, and
loop detection rejected it.

This is not a huge problem; if he returns just the top lines of the form, it
will have a unique document/draft designation which should make the message
body unique. Easy fix (or would be, if he took advice more readily!)

But it does raise three questions:

1. Am I correct that the sender's address IS considered as part of duplicate
detection?
2. What is the probability of an accidental CRC match between non-identical
message bodies?
3. How long does LISTSERV retain CRCs of previous messages for duplicate
detection?

Thanks for any enlightenment you can provide.

Hal Keen


############################

To unsubscribe from the LSTOWN-L list:
write to: mailto:[log in to unmask]
or click the following link:
http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTOWN-L&A=1