(FAQ) Does Outbreak Protection work on mail collected via POP?

Does Outbreak Protection work on mail MDaemon collects via POP?

Yes - in most cases. There are a couple requirements for OP to be applied to DomainPOP or MultiPOP mail:

  • MDaemon requires that the SMTP MAIL value is preserved in a 'Return-Path' header. If this value is missing or invalid, the message will not be passed to OP.
  • There must be a 'Received' header and it must include the sending IP address.  Note that most servers do not include the IP address in the Received header as it's optional. This Received header must be the top-most Received header.

MDaemon requires these to make OP (which is designed for SMTP) to work with as many environments as possible. Without the required info OP would not be accurate.