Warnpost, nowarnpost, copywarnpost, errwarnpost Channel Options

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Warning messages (warnpost, nowarnpost, copywarnpost, errwarnpost)

In addition to returning messages as undeliverable, the MTA sometimes sends warnings detailing messages that it has been unable to deliver for some period of time. This is generally due to timeouts based on the setting of the notices channel option, although in some cases channel programs may produce warning messages after failed delivery attempts. The warning messages contain a description of what's wrong and how long delivery attempts will continue. In most cases they also contain the headers and possibly some additional content from the message in question.

The MTA will also optionally send a copy of certain warning messages to the local postmaster. This can be somewhat useful for monitoring the state of the various MTA queues, although it does result in lots of traffic for the postmaster to deal with.

The options warnpost, copywarnpost, errwarnpost, and nowarnpost are used to control the sending of warning messages to the postmaster. warnpost tells the MTA to send a copy of all warning messages to the postmaster unconditionally. copywarnpost instructs the MTA to send a copy of the warning to the postmaster unless the originator address on the as yet undelivered message is blank; i.e., the postmaster gets copies of all warnings of undelivered messages except for those as yet undelivered messages that are actually themselves reports on bounces or notifications. errwarnpost instructs the MTA to only send a copy of the warning to the postmaster when the notice cannot be returned to the originator. No warning messages are ever sent to the postmaster if nowarnpost is specified.

If no *warnpost channel option is in effect the default is taken from any *sendpost channel option setting. If no such setting exists the default in releases prior to Pasilla was copywarnpost. As of Pasilla the default has been changed to nowarnpost.