Handle connection request failures for TCP/IP

The main causes for failed connection requests at a Distributed Relational Database Architecture™ (DRDA^®) server configured for TCP/IP use is that the DDM TCP/IP server is not started, an authorization error occurred, or the machine is not running.

• Server is not started or the port ID is not valid
  The error message given if the DDM TCP/IP server is not started is CPE3425.
• DRDA connect authorization failure
  The error messages given for an authorization failure is SQ30082.
• Server not available
  If a remote server is not up and running, or if you specify an incorrect IP address in the RDB directory entry for the application server (AS), you will get message CPE3447.
• Connection failures specific to Interactive SQL
  Sometimes when you are running a CONNECT statement from Interactive SQL, a general SQ30080 message is given.
• Not enough prestart jobs at server
  If the number of prestart jobs associated with the TCP/IP server is limited by the QRWTSRVR prestart job entry of the QSYSWRK subsystem, and all prestart jobs are being used for a connection, an attempt at a new connection will fail with these messages.