Command: md5cache

  Format: md5cache <time>

Sets the time period for which listmanager retains the MD5 checksum
for the message body for each submission sent to the list.  If, in that
time period, a message body arrives that generates the same MD5 checksum,
the message is rejected.  This prevents duplication of submissions
without having to make the list moderated.  Note that the message
headers are not checked, so sending precisely the same message
at different times or from different addresses will still be rejected.
However, sending a message that differs by even a single character will
produce a different checksum, and thus the second submission will pass
this check.

To quote the MD5(1) man page, it is "conjectured that it is computationally
infeasible to produce two messages having the same message digest, or to
produce any message having a given prespecified target message digest."
What this means to you is that it's extremely unlikely that listmanager
could reject two different postings that result in the same checksum.

A value of "0" or "none" disables this feature.

The time is composed of a number and letter.  The letter possibilities
are as follows: w (week), d (day), h (hour), m (minute) and s (second).
These can be used in any combination for the desired effect.  For example:

	md5cache 12w6d

This would prevent the same message from being sent to the list for
12 weeks and six days.  By extension, 12w6d is the same as 90d, and so on.

You must be a list owner to use this command, and must have previously
selected your list with the "select" command.

See also: loop-detect select
