> We are running LISTSERV on a Windows NT host (ddoc.adlt.com) and sending mail
> via a Lotus Domino SMTP MTA running on another Windows NT host
> (thorium.adlt.com).  Many of our outbound messages fail, seemingly due to a DNS
> failure on the receiving end related to the address
> [log in to unmask]  Two typical traces appear below.  My questions
> are: 1) where does "[log in to unmask]" come from (it's not in the
> list header anywhere); and 2) any suggestions to fix this problem?

It's the address used by LISTSERV to receive delivery errors for the list
named hiddtest.  The failures you are getting are because the hostname
DDOC.ADLT.COM is not in the DNS.  Many SMTP servers check that the Return-path
(SMTP MAIL FROM) address is in the DNS as an anti-spam measure.
Presumably, that host is the name of your LISTSERV machine.  It needs to be
in the DNS anyway, if it's ever going to receive any mail.