Given the information provided in SYS$REM_ID
(remote ip address and port number),
what's the best way to determine the username associated with the telnet
(or other tcp/ip) client, when that client software is running on another
member of the same VMS cluster?

I have to believe that this is "an already solved problem."

All cluster members are running Multinet, of course.

So far today, what I've come up with is the following:

From the IP address one can determine the remote cluster decnet node name
using a table lookup.

One could then use rsh or equivalent to the remote node to get the output of
MULTINET SHOW/CONNECTIONS=PID
and search that list for the port number to obtain the owning process id.

One could then search the output of
SHOW USERS/FULL/NODE=whatever
for the process id and obtain the associated username.

But that's gross :-)

Thanks for whatever help you can provide.

Selden