Assuming some ambiguity in your original question/observation, LISTSERV
will distribute mail over the LISTSERV Bitnet Backbone and THEN
possibly gateway the mail to Internet addresses.
 
This algorithm is controlled, in part, by any registration of
Internet/Bitnet equivalences in the BITEARN NODES database at the
originating LISTSERV site for each Internet subscriber's address.
 
Thus, if I have a subscription to LDBASE-L on Bitnet node UKANVM aka
UKANVM.CC.UKANS.EDU using my host address on oas.psu.edu (which is
equivalenced in the the BITEARN NODES database to PSUADMIN), LISTSERV
will Distribute LDBASE-L postings to me via the LISTSERV@PSUVM,
(routing via the LISTSERVs @ KSUVM + MIZZOU1) and then "explode" it to
my Internet address, since PSUVM is the closest LISTSERV backbone site
to PSUADMIN.
 
I think at PSUVM, where my address gets "exploded", is the place where
DOMAIN NAMES comes into effect.
 
/Pete ([log in to unmask])
--
Peter M. Weiss                     | oas.psu.edu postmaster
31 Shields Bldg -- Penn State Univ.| "Connectivity is more than a Connection"
University Park, PA USA 16802-1202 | E. Michael Staman, _The Circuit_, Apr 92