TCP/IP uses services from other address spaces in its processing. While TCP/IP waits for availability of those services, it is recommended that you verify that the OMVS, resolver, and VTAM® address spaces have completed initialization before starting TCP/IP. If using automation to start TCP/IP, have it look for the BPXI004I, EZZ9291I, and IST020I messages, respectively, before issuing the START command.
For information on how the resolver can be started, see Starting the resolver. You can use the resolver's MODIFY DISPLAY command to check that the resolver is active and what resolver setup statements are being used. For the syntax and usage of the command, see z/OS Communications Server: IP System Administrator's Commands.