Allow Duplicate Posting

A duplicate posting occurs when one person attempts to post a seemingly identical message to the same mailing list more than once in one day. Please note: Archives must be be kept for at least one day for duplicates to be detected.

ListManager looks at the first 200 characters to determine if a posting appears to be a duplicate. The reason for this is that some "automatic answer" programs (such as the "vacation" program) will automatically reply to anything they receive by adding a "I'm on vacation" sentence to the top of the message and quote the rest of the message. ListManager will catch the duplicate posting, since the top of the message will be identical.

Normally, duplicate postings are the result of the author not being careful and sending the same message twice, or of some Internet mail error where the same message is delivered twice.

By default, ListManager rejects duplicate postings. Normally, you will want to leave this default setting as it is since, there usually is no good reason why your list members would want to receive the same message twice. Also, this feature is quite effective as a mail-loop prevention technique, when people attach a misbehaving "automatic email answering" program to their email address. Most "vacation" programs are well behaved and do not answer list-mail. However, people sometimes decide to write their own "vacation" program or other automatic email generating program and this can cause problems on a list. This feature takes care of this problem.