Step 3: Configure VMCF and TNF

The Pascal socket interface uses the IUCV/VMCF services for a limited set of inter-address space communication flows. As a result, if you are using any applications (provided by IBM® or others) that use the Pascal socket API, you must ensure that the Virtual Machine Communication Facility (VMCF) and Termination Notification Facility (TNF) subsystems are active before the applications are started. TCP/IP provides the following applications and commands that use the Pascal socket interface:

SMTP and LPD servers
TSO HOMETEST, LPQ, LPR, LPRM, LPRSET, TELNET, and TESTSITE commands

If you are using any of these applications or commands, you need to set up VMCF and TNF.

You can configure VMCF and TNF in two different ways: as restartable subsystems or as non-restartable subsystems.

If you configure VMCF and TNF as restartable subsystems and you want the VMCF node name to be used as a default host name during TCP/IP initialization (when no other host name can be located), VMCF must be started before TCP/IP.

Tip: The host name value is typically specified on the TCPIP.DATA HOSTNAME statement.

Guideline: The VMCF node name is used as a system-name qualifier when the TCPIP.DATA file is being processed and it is used by the SMTP server as the NJE node name. For this reason, you should use the MVS™ system name for the VMCF node name specification and specify the NJE node name explicitly by using the NJENODENAME statement in the SMTP configuration data set.