IP Services: Define a user ID for the system resolver with an associated OMVS segment

Description: Starting with z/OS V1R13, the system resolver uses z/OS UNIX services in the resolver address space. Use of z/OS UNIX services requires the resolver to have an OMVS segment associated with its user ID. If you do not define a user ID for the resolver with an associated OMVS segment, the resolver initialization will fail and the TCP/IP stack initialization will not be able to complete with message

EZZ9315E TCP/IP WAITING FOR RESOLVER TO INITIALIZE.

Element or feature: Communications Server.

When change was introduced: z/OS V1R13.

Applies to migration from: z/OS V1R12.

Timing: Before installing V2R1.

Is the migration action required? Yes, if you do not have a user ID defined for the system resolver that has an associated OMVS segment, which provides access to z/OS UNIX services.

Target system hardware requirements: None.

Target system software requirements: None.

Other system (coexistence or fallback) requirements: None.

Restrictions: None.

System impacts:

If you do not define a user ID for the system resolver that includes an OMVS segment, the resolver initialization will fail and the initialization of all TCP/IP stacks will be delayed. The following messages might be issued to describe the initialization failure scenario:

IEF695I START RESOLVER WITH JOBNAME
RESOLVER IS ASSIGNED TO USER RESOLVER
IEF403I RESOLVER - STARTED - TIME=13.40.06
ICH408I JOB(RESOLVER) STEP(RESOLVER) CL(PROCESS )
OMVS SEGMENT NOT DEFINED
EZZ9301E RESOLVER ENDED ABNORMALLY
IEF450I RESOLVER RESOLVER - ABEND=SEC6 U0000
REASON=0F01C008 TIME=13.40.07
IEF404I RESOLVER - ENDED - TIME=13.40.07

Related IBM Health Checker for z/OS check: None.

Steps to take: Follow these steps:

If you already have a user ID for the system resolver started procedure, and you explicitly defined an OMVS segment for the ID, or an OMVS segment was created automatically through the RACF automated assignment of unique UNIX identities support, no action is required.
If you already have a resolver user ID but it does not have an OMVS segment, you must define an OMVS segment for the resolver user ID.
If you do not have a resolver user ID, you must create one that includes an OMVS segment.

The following information is an excerpt of the SEZAINST(EZARACF) sample job that you can use to define a user ID with an OMVS segment and assign it to the system resolver started procedure. You might need to modify the sample values that are specified in the commands for your environment. For example, the UID, Default Group, and Resolver user ID values are sample values.

//*=========================== RESOLVER ===============================
//*====================================================================
//*====================================================================
//*
//* Create the userid and its OMVS Segment for the daemon and
//* add it to the STARTED Class which is activated in this job.
//*
//* If you chose not to use the RACF STARTED Class,
//* the entry should be placed in the started procedures table ICHRIN03.
//*
//RESOLVER EXEC PGM=IKJEFT01
//SYSTSPRT DD SYSOUT=*
//SYSTSIN DD *
SETROPTS CLASSACT(STARTED)
SETROPTS RACLIST(STARTED)
SETROPTS GENERIC(STARTED)
ADDUSER RESOLVER DFLTGRP(OMVSGRP) OMVS(UID(42) HOME('/')) -
NOPASSWORD
RDEFINE STARTED RESOLVER.* STDATA(USER(RESOLVER))
SETROPTS RACLIST(STARTED) REFRESH
SETROPTS GENERIC(STARTED) REFRESH
//*

Reference information: For information about defining and assigning a user ID for started procedures, see "Using Started Procedures" in z/OS Security Server RACF Security Administrator's Guide.

For information about defining an OMVS segment, see "RACF and z/OS Unix" in z/OS Security Server RACF Security Administrator's Guide.

For general information about the system resolver, see "Steps for defining the resolver address space" in z/OS V2R1.0 Communications Server: IP Configuration Guide.