ajaydec,
temporary mailboxes are a means to communicate between processes.
However, the communicating processes must agree about WHICH mailbox. That is made known by defining the name of that mailbox in LNM$TEMPORARY_MAILBOX.
(which itself is a name pointing to a logical name table).
For the cooperating processes to be able to translate the mailbox name into the correct MBA device, they must all agree upon WHICH table it is defined in, AND, must have it in their LNM loopup list. By default, LNM$TEMPORARY_MAILBOX is the LNM$JOB for the process. That means, a process and all its sub-processes, and noone else, can communicate via temporary mailboxes of that process tree. Normally the processes have read and write access to that table, so no extra measures needed.
_IF_ processes are to communicate with other processes, _THEN_ LNM$TEMPORARY_MAILBOX must be a table shared between them, and the process creating the mailbox must have WRITE access to that table.
Most common is the use of LNM$GROUP:
$ DEFINE LNM$TEMPORARY_MAILBOX LNM$GOUP/TABLE=LNM$PROCESS_DIRECTORY
Remember, the process creating the mailbox needs GRPNAM privilege, OR, the table needs an ACL allowing write access.
If users of different UIC groups are to share LNM$TEMPORARY_MAILBOX, then you should create a (application-) LNM table, regulate access via an identifier based ACL, and UAF GRANT that identifier to the relevant users.
(you, and several layered products, mention using LNM$SYSTEM as LNM$TEMPORARY_MAILBOX, but I have to MOST STRONGLY discourage that use (abuse!).
hth
Proost.
Have one on me.
jpe
Don't rust yours pelled jacker to fine doll missed aches.
