At 09:23 12/31/2002 Tuesday, Andrew Bosch wrote:
 >I have noticed that when Listserv uses the list address in the To line, some
 >mail servers return a 5xx error message with the text "Relay denied" or
 >similar. If I use Full822 headers or Short822 headers, where the recipient is
 >listed in the To line, then these same recipients successfully receive the
 >messages. Is anyone else having this problem and what are you doing about
 >it?
End Reply

When you "force" only one e-mail per userid, then what mostly likely
occurs is that you are no longer taking advantage of the LISTSERV
Distribute Backbone, which means that the "closest" cooperating LISTSERV
host to the target subscriber is NOT being used.  THUS, the client SMTP
sending mail to the [subscriber's] server is different from where in the
Backbone it is being sent.

It could also mean that depending upon timing, that occasionaly,
seconardary MXes are being used and it may be that those secondaries
("less preferred") are incorrectly configured, further compounding the
obfuscation factor.

[Hardly anyone every speaks of the Distribute Backbone anymore, since it
was more often "seen" in the days of BitNet.  It is still used though.]

/Pete Weiss -- a mainframe dinosaur