How ListManager Decides Who to Unsubscribe

There are four ways to unsubscribe from a ListManager mailing list:

1. Log into the discussion forum interface, select My Forums, and click "unsubscribe" next to a list.

2. Send the command "unsubscribe listname" to lyris@your-server-name.com.

3. Send the command "unsubscribe listname your-email-address" to lyris@your-server-name.com.

4. Forward any posting you receive from a mailing list to the unsubscribe-listname@your-server-name.com address.

If an unsubscribe request is made with the "unsubscribe" command sent to lyris@this-ListManager-server.com, as in "unsubscribe jazztalk", then the person named in the From: field is unsubscribed. If the email address named in the From: field is not a member, ListManager returns a message to that person saying that they could not be unsubscribed.

ListManager also provides the option of naming an email address on the "unsubscribe" command line, such as the command "unsubscribe jazztalk bob@example.com". In such a case, if unsubscribe confirmation are enabled for the list, then a confirmation message is sent to the subscriber, then ensure that they are same person and not that someone else is trying to unsubscribe them.

When mail is received at the "unsubscribe-listname@…" address, ListManager tries to determine who the subscriber is and automatically removes them. In most situations, this works very well.

The ListManager unsubscribing logic for unsubscribe requests received at the "unsubscribe-listname@…" is fairly sophisticated, and here is how it works. When ListManager receives a message to the "unsubscribe-listname@…" address, ListManager goes through the following steps:

1. First looks for X-Lyris-Member-ID in the header. If it's there, that's who gets unsubscribed. This catches almost all cases, except when the forwarding program strips out the headers (such as in this example).

2. Looks for a purgeid tag in the header (X-Lyris-To:) and then in the body. If it's there, that person gets unsubscribed. Note: purgeid tags are "cleaned up" before they are re-posted to a list (i.e., in quoted message), by removing the square brackets. In the example below, the square bracketed email address clearly identifies "wantsoff", so that who gets unsubscribed. Also note that MS-Mail generated addresses with the text [SMTP:...] are correctly skipped by ListManager.

3. Looks at the Return-Path (the MAIL FROM:<> sender), and sees if it's a member. If it is, then this is likely a forwarded message, and unsubscribe that person. Pegasus Mail does this.

4) Finally, if none of the above is valid, the person named in the From: header is unsubscribed.