On Tue, 8 Jan 2002 12:32:55 -0500, Gary Bannister <[log in to unmask]> wrote:

>I would like to know how Listserv normally handles a posting to a domain
>that appears to no longer exist (i.e., the MX records for the domain can
>not be determined). With my current setup (1.8d under BSD/OS 4.2), when a
>posting is sent it is broken into envelopes of 100 addresses.  If one of
>the addresses contains a domain for which the MX records can not be
>located, the message "Can not check MX records for recipient host <DOMAIN>"
>appears in the logfile and the posting will sit in the spool directory
>until the domain becomes reachable.

Isn't this the same issue you raised last Sept and was answered by Valdis in
msg:
http://peach.ease.lsoft.com/scripts/wa.exe?A2=ind0109&L=lstsrv-l&F=&S=&P=8161

The short answer is that LISTSERV never delivers to end recipients by itself.
It always hands this off to an MTA (Mail Transfer Agent) such as sendmail.
Normally LISTSERV composes BSMTP 'packages' (in your case of 100 recipients)
and mails that 'package' to sendmail.  LISTSERV has a very simple SMTP process
doing this that expects that the MTA will accept the entire 'package' without
question.  Then when the MTA is attempting to deliver the actual mail, if it
finds a bad address, it is the job of the MTA to prepare an error reprot
message and deliver that back to LISTSERV.  In short, the MTA must not attempt
DNS lookup verification on the domains at the time it accepts the mail from
LISTSERV.  Valdis gave you some configuration recommendations for sendmail
that you reported did the work.  Is that no longer the case?