In 2014, starting with Yahoo! and quickly followed by AOL, several of the large ISPs implemented aggressive DMARC authentication policies that created giant headaches. Stuck between a rock and a hard place with no advance warning, list administrators were forced to resort to a variety of circumventions, from deleting all Yahoo and AOL subscribers, to putting the list address in the "From" field, thus causing all private replies to be broadcast to the list without warning and inviting mail clients to submit out-of-office messages to the entire list.  The solution L-Soft developed at that time for LISTSERV does not require anyone to make compromises or lose any functionality -- not even the Yahoo and AOL subscribers.

This section discusses the DMARC authentication protocol and how LISTSERV complies with it.

Note: DMARC rewriting is not available for z/VM because because there is no DNS query support in the z/VM version.

Contents:

13.1 What is DMARC?

13.2 What is Binding Operational Directive (BOD) 18-01?

13.3 How does LISTSERV comply with DMARC?

13.4 Debugging DMARC errors in LISTSERV

13.5 DMARC_NO_REWRITE