We have just installed the latest version of Listserv - Version 15.  We have 
Lotus Notes as our corporation's email package.  Lotus Notes sends and 
receives email through the same smtp port - 25.  Listserv is sending email out, 
but is not listening for emails.  Listserv, by default, works with port 25 as well. 
Listserv Tech support suggesting changing the port listserv listens on, but 
that would involve changes to our dmz which we prefer not to do.  Can 
someone point us in a direction?  What would the impact be of not enabling 
the listening at all?  Users can work with http requests, and we can work with 
the web interface and with the listserv server directly.

Thanks