On Fri, 23 Jul 1993 16:13:31 CST Bill Harvey <[log in to unmask]> said:
 
>On Fri, 23 Jul 1993 15:49:13 EDT, John Arnfield
>   <[log in to unmask]> said:
>>I have recently been asked to enter a subscription for a person using an IP
>>number address, i.e. of the form
>>           userid@[141.65.128.48]
>
>This is a valid address.  LMAIL, LISTSERV's DIST protocol, XMAILER,
>and IBM's SMTP (for VM) all support this format.  (I don't have access
>to SMTP for MVS, so couldn't test it, but I'm pretty sure it does too.)
 
Indeed it is a  valid address, but it is not  formally supported by LMail
or LISTSERV.  There are configuration cases  where it will works,  and in
other cases it may not work (for  instance, with LMail this only works if
you have  a default  entry in the  domains table). This  is some  sort of
anachronism  which  was   furthermore  designed  for  temporary/debugging
reasons.  For instance,  if I  am  setting up  a  new host  and run  into
problems, that is one way of sending mail to the person in charge of that
machine even  though the name server  is broken (another is  to telnet to
his SMTP  port). It is even  less appropriate for inclusion  in a mailing
list than  a source route,  and LISTSERV  does not support  source routes
(LMail  does, because  they are  very useful  for routing  things around,
which is part of LMail's job).
 
  Eric