On Fri, 21 Apr 1995 15:04:54 -0400 "Lee J. Silverman" <[log in to unmask]> wrote:
>>    I have just gotten an error message from my LISTSERV stating that someone
>> tried to sign on with an unknown domain. The information to the right of the
>> @ are all numbers (i.e. 192.245.137.1) The host postmaster doesn't recognize
>> this and neither do I. I deleted the user since it will spawn countless
>> error-messages. Has anyone else run across this sort of thing before?
>
>        The user is trying to use their IP address instead of an internet
>domain name to subscribe to your list.  There's a few issues here:
>
>1) 192.245.137.1 is an unassigned IP address served by feenix.metronet.com.
 
False.  The DNS (Domain Name-Servers) for the 'MetroNet.COM' domain
are 'UTDALLAS.EDU', 'INFINITY.C2.ORG', and (surprise!) 'FEENIX.METRONET.COM'.
 
So, this IP-address *is* assigned, and, obviously, it's being used.
 
>   IP addresses ending in .1 are typically routers or other control hardware,
 
False.  As is also the case for the 'MetroNet.COM' domain,
one of the DNS sites for the 'UVIC.CA' domain is '142.104.6.1'.
By local convention, UVic uses addresses ending in '.254' for routers.
Your mileage may vary.  :-)
 
>   so trying to send email to [log in to unmask] doesn't make much sense
>   if it's just the network router.
 
If that specific host were solely a router, then I would agree.
 
>2) I think that if a user wants to specify the IP address of their machine
>   in their email address, the correct form is user@[192.245.137.x].
 
Correct.
 
>   I don't have enough experience with listserv to know if it's possible
>   to handle an address of this form.
 
LISTSERV will handle it, without any problems,
simply because LISTSERV doesn't actually do any SMTP mail-delivery;
it delegates that task to the standard SMTP-server at the host site.
As long as the '[' and ']' characters are present,
a correctly-functioning SMTP-server will handle it.