The best value for "Loopcheck=" is no value, ie edit the list header and
remove the string "Loopcheck= Nobody". Any other value apart from "Full",
which is the default, means that some or all of the loop checking
routines are disabled. "Nobody" means that LISTSERV is not allowed to
look into the message body to decide whether or not something is a
delivery error; it is to rely solely on the 'Subject:' field. As you can
imagine, this is a very dangerous option: it means that any mailer not
using one of the "standard" subjects known to LISTSERV will cause a loop.
"None" is even worse, it tells LISTSERV that, by definition, anything
that reaches its reader is NOT a delivery error. These two options should
never be used unless the list is moderated. Even if the list is moderated
they are not recommended, especially if the moderator is not the list
owner (ie administrator). I actually regret having implemented these
options, it really scares me to think that people are using them without
knowing what they do.
"Notocount" means that LISTSERV should not count the 'To:' fields in the
message body and decide it is seeing a delivery notice if there are too
many; "MaxTo(nnn)" orders it to allow up to the specified amount of 'To:'
fields, the default is 10. This is the one sub-option of the "Loopcheck"
keyword that can be useful - for digests. The code that counts the 'To:'
field is here as a kind of "last resort" action anyway, to prevent
infinite loops, but it won't stop the redistribution of the first 'nnn'
nastygrams. If you disable this routine it means loops can become
infinite, but it doesn't have any effect on the actual detection of new
loops.
Finally, the latest addition, "NoCRC", means you don't want to suppress
duplicate messages on the list, ie if RSCS at FOO becomes crazy and sends
you 200 copies of the same posting, as it happened for LSTSRV-L, INFO-VAX
and many other lists about 6 weeks ago, you will happily redistribute the
200 copies. I added this option as a kind of "emergency bypass" in case
the new code that detects such duplicates should break and start
rejecting all postings. Fortunately this did not happen, so you can
forget about it.
Eric
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