> Is it possible to have UNIX listserv on one box and use another existing
> mail server for delivery ? If yes, how?
 
Yes, it's possible, although not exactly advisable, as you incur
roughly double the amount of processing (once by your sendmail,
once again by the mail server's sendmail). On a list by list
basis you can use the Internet-via= keyword to force
source-routed delivery through another host.
 
> We just want to utilize the existing mail server
> without configuring a new mail serve on our listserv box.
 
You could also install a "distribute-only" version of LISTSERV on
the mail server, which would actually do a better job. Your
LISTSERV would send only one copy of the posting to the mail
server, which would explode it locally, without incurring the
overhead I mentioned above. It's a small extra cost, but it saves
a pile of resources, especially if you have large numbers of
users on the mail server that subscribe to a lot of lists.
 
> What are the trad-offs?
 
For having the mail server deliver all the mail using Internet-via:
 
Pro: You can use the horsepower of the mail server to do your
     delivery.
 
Con: You gain nothing on your LISTSERV host, as it still has to
     generate and transmit all the mail via the mail server,
     which has to accept and then re-transmit the messages to the
     final destination.
 
     You add complexity to the list header -- one more thing to
     explain to the list owners.
 
Installing a distribute-only copy of LISTSERV on the mail server:
 
Pro: You get to use the horsepower of the mail server to deliver
     your mail.
 
     Your LISTSERV generates only one job to the mail server for
     arbitrarily large numbers of recipients.
 
     Transparent to list owners and users.
 
     Reduces traffic on your local network, allowing you to
     postpone transmission capacity upgrades
 
Con: You have to pay for the distribute-only LISTSERV license.
 
     You have to convince someone to install LISTSERV on the mail
     server.
 
Fortunately, a distribute-only license is pretty cheap (check
with [log in to unmask] for actual pricing), so you may want to look
at this as an option. Also, since the distribute-only copy of
LISTSERV wouldn't be supporting lists, it's essentially an
install-and-forget thing (aside from occasional license key
updates).
 
-- db