At least two people have suggested LSMTP. LSMTP is available for Windows
2000/NT and OpenVMS. The individual who asked the original question did not
identify the OS on which LISTSERV is currently running, however, if he is
using Sendmail Switch as the MTA for LISTSERV, the OS is probably some
flavor of Unix or Linux. He could run LSMTP and LISTSERV on different boxes
running different OSes, however, this would simply add complexity to his
environment, and he would still need to run a different MTA on the LISTSERV
server to handle inbound traffic. The only way to use LSMTP as both the
inbound and outbound MTA for LISTSERV would be to migrate the LISTSERV
service from its current OS platform to an OS platform supported by LSMTP.

We used open source sendmail as the MTA for our LISTSERV server for over
five years. We recently moved our LISTSERV service from a dedicated server
to one of the servers in our central mail cluster, where we run Sendmail
Switch. We have over 10,000 lists on the LISTSERV server, and we create
approximately 4,000 new lists each semester, so we have written scripts to
automate many list creation and maintenance tasks, including the addition
and removal of list-related aliases, and the deployment of the updated
aliases file.

List-related aliases are maintained only in the aliases file on the server
where the LISTSERV service is hosted. Modification and deployment of the
aliases file for that server is handled by a script, rather than by the
Sendmail Switch administrative interface. The script simply places copies
of the aliases file in the appropriate locations and issues the 'newaliases'
command to deploy the aliases file.

--
Paul Russell
Senior Systems Administrator
O&E Messaging Services Team
University of Notre Dame