Loopcheck Keyword
Loopcheck= Normal | Full | None | Noorigin | Nobody | NoCRC | NoSpam | Spam-Delay(n)
This keyword is not available in LISTSERV Lite.
This keyword determines the type of loop checking performed by LISTSERV to avoid perpetuating mail loops. The default is "Loopcheck= Normal". Loop checking is configured on a list-by-list basis.
|
Warning: Always use this keyword with caution. Misuse of this keyword can allow mailing loops onto your list.
|
The various "Loopcheck=" parameters are defined as:
Normal |
LISTSERV uses the most important loop-checking heuristics to check incoming mail for loops. This is the default and should only be changed for troubleshooting purposes. |
Full |
LISTSERV uses its full suite of loop-checking heuristics to check incoming mail for loops. |
None |
All LISTSERV loop-checking and "command-to-list" checking is disabled for this list. This setting tells LISTSERV that, by definition, anything that reaches it is not a delivery error. It is never a good idea to use this parameter except in special cases where a bug is suspected in the loop-checking heuristics. Generally this parameter should not be used without checking with L-Soft first, and only for the diagnosis of an existing problem. |
Noorigin |
Allows the list owner to disable the check for "known mailer origins" such as MAILER, POSTMASTER, ROOT, UUCP and others. Mail whose "From" field is the address of the local mailer is still trapped, but wildcard checks on the mail origin are disabled. |
Nobody |
Allows the list owner to disable the check for identical text in the body of incoming mail only. LISTSERV relies only on the "Subject" field of the mail message to determine whether or not mail is looping. 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. |
NoCRC |
Allows the list owner to disable the CRC (cyclical redundancy check) of incoming mail. CRC loop checking calculates a "checksum" based on the contents of the mail message and compares it to other incoming mail to spot duplicates. |
NoSpam |
Allows the list owner to disable the anti-spam filters to incoming mail. |
Spam-Delay(n) |
Allows the list owner to modify the number of minutes LISTSERV holds mail from non-subscribers before releasing it to the list. The assumption is that, within n minutes, a spam alert may or may not arrive regarding non-subscriber mail. The list owner can disable this function for the list by coding "Loopcheck= Spam-Delay(0)", or can tune it to his preference by simply specifying the number of minutes for LISTSERV to hold the mail. The default is 10 minutes, or "Spam-Delay(10)". |
L-Soft does not recommend changing "Loopcheck=" from its default of "Normal" unless you are prepared to accept the very likely possibility of a mail loop occurring on your list, a situation for which L-Soft would not and could not be held responsible. The only exception would be the "Loopcheck= NoSpam" (which might be necessary to keep administrative mail to multiple lists on a single host from triggering the anti-spam filter) or "Loopcheck= Spam-Delay(n)" options, neither of which stops canonical mail loops per se.
LISTSERV® is L-Soft's email list management software, originally developed by Eric Thomas in 1986. Visit the LISTSERV® Resource Center for more complete documentation.
LISTSERV® is a registered trademark. The trademark identifies LISTSERV® as a brand of email list management software developed by L-Soft.
|
