X400: Err Msg: ERROR 3 (RTS): RTS Open Refused...

The information in this article applies to:

• Microsoft Mail Gateway to X.400, version 3.2

SYMPTOMS

Version 3.2 of Microsoft Mail Gateway to X.400 may give the following error:

   ERROR 3 (RTS): RTS open refused (session limit exceeded)

CAUSE

So that it can always leave one outgoing connection available, the X.400 gateway version 3.2 can accommodate no more than three incoming connections in a given time period. How the Gateway counts sessions during that time period explains why this error is returned.

Consider this example sequence:

• The gateway receives an incoming connection and holds it open for a long time (because it has several messages to receive).
• While the first connection is open, the gateway receives a second incoming connection, which it accepts, processes and closes.
• While the first connection is still open, the gateway receives a third incoming connection, which it accepts, processes and closes.
• At this point the gateway calculates that the three-session limit has been reached within a specific interval, so when a fourth incoming connection request is received it is refused at the RTS level.
• The gateway refuses subsequent incoming connection requests until the first connection is finished and closed.

RESOLUTION

If this error becomes a problem, install another X.400 gateway on another postoffice to spread the mail traffic.

If you have External running, try starting the gateway with the -md option (mailer disable). With -md on, the gateway puts incoming mail in the postoffice, but lets External finish the job by moving the mail to the recipient's mailbag. This also saves memory on the X.400 Gateway.