This is from V18A RELNOTES.  Hope it helps.  Note that there is a
LISTSERV configuration that your LISTSERV maintainer will have to
do.
 
         Description of the changes for release 1.8a of LISTSERV
         -------------------------------------------------------
                  Copyright L-Soft international, 1993
 
                           December 7th, 1993
 
(many many lines deleted:)
 
******************************************************
* Usability: New "List-Address=" list header keyword *
******************************************************
 
Version  1.8a adds  a  new  "List-Address=" list  header  keyword, and  a
corresponding  LIST_ADDRESS configuration  option (to  be added  to LOCAL
SYSVARS)  to establish  a  system default.  This  keyword determines  how
LISTSERV announces the  list address in the header  of messages delivered
to the list: NJE  vs Internet address, short vs long  list name, etc. The
default  options  (when  neither  "List-Address="  nor  LIST_ADDRESS  are
defined) corresponds to the behaviour of version 1.7f, ie short list name
and NJE address.
 
The format of both keyword and configuration statement is simply:
 
                           name_info@host_info
 
The first  token (name_info) can  be either  LISTNAME or LIST-ID.  Do not
attempt  to specify  the  actual  list name.  Use  LISTNAME  if you  want
LISTSERV to use the "short" list  name (always available), and LIST-ID if
you would rather see the "long"  list name ("List-ID=" keyword). If there
is no "long" name, the short name is substituted.
 
The  second token  (host_info)  can be  either NJE,  FQDN,  or the  fully
qualified domain  name of your choice.  That is, you may  type the actual
hostname  that you  want LISTSERV  to  use, which  may be  useful if  the
machine on which LISTSERV is running is known under several hostnames.
 
If you only  want to override one  of the two parts of  the list address,
you do not need  to specify the other. For instance, if  you only want to
change the  hostname, you can  enter "List-Address= XYZ.EDU" in  the list
header and  let the left-hand part  default from the value  of the system
default in  LOCAL SYSVARS.  Similarly, "List-Address= List-ID"  takes the
right-hand part from the system default. To avoid bad surprises, LISTSERV
will also accept a comma in lieu of @-sign in the list header, or a blank
in LOCAL SYSVARS. Here are a few examples:
 
- "List-Address= FQDN" announces the list  under the Internet address for
  the  LISTSERV host,  if one  is available  (for BITNET-only  sites this
  setting has no effect).
 
- "List-Address= List-ID@FQDN" uses  the long list name  and the Internet
  hostname.
 
- "List-Address=  [log in to unmask]"  uses the  short  list  name and  the
  hostname XYZ.EDU.
 
- "List-Address= [log in to unmask]" is not  valid. Always specify LISTNAME or
  LIST-ID for the left-hand part.
 
To announce  all lists under  the Internet  hostname by default,  add the
following statement to LOCAL SYSVARS:
 
LIST_ADDRESS = 'FQDN'
 
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