IP Services: Update automation to monitor resolver address space initialization completion messages

Description

In releases before z/OS V2R1, the resolver address space initialization failed if errors were detected in the setup file. Beginning with z/OS V2R1, the resolver processes the entire resolver setup file during resolver address space initialization. When the resolver detects syntax errors or when it does not recognize the resolver setup statement, the resolver ignores the setup file statement and the resolver initialization completes successfully with warning messages. Ignoring the setup file statement might result in the resolver using default settings for some resolver setup statements if the statement was specified with errors.

If the resolver issues warning messages during address space initialization, the resolver issues message EZD2038I instead of message EZZ9291I when the initialization completes.

Table 1 provides more details about this migration action. Use this information to plan your changes to the system.

Table 1. Information about this migration action
Element or feature:	Communications Server
When change was introduced:	z/OS V2R1.
Applies to migration from:	z/OS V1R13.
Timing:	Before the first IPL of z/OS V2R2.
Is the migration action required?	Yes, if you customize the resolver and want to correct any errors that the resolver finds in the resolver setup file.
Target system hardware requirements:	None.
Target system software requirements:	None.
Other system (coexistence or fallback) requirements:	None.
Restrictions:	None.
System impacts:	The resolver might initialize with the incorrect configuration because of errors in the setup file, which might cause applications issuing resolver API calls to get erroneous results.
Related IBM Health Checker for z/OS check:	None.

Steps to take

If you customize the resolver and want to detect when the resolver ignores errors in the resolver setup file during address space initialization, do the following:

Monitor resolver address space initialization for message EZD2038I RESOLVER INITIALIZATION COMPLETED WITH WARNINGS.
Issue the MODIFY RESOLVER,DISPLAY command after system initialization completed to determine if the following message has been issued in the display output:
```
EZD2039I WARNINGS ISSUED DURING RESOLVER INITIALIZATION
```

If the resolver issues the message EZD2038I or EZD2039I, do the following:

Collect the system console messages that are issued by the resolver during resolver address space initialization.
Contact the system programmer. The system programmer needs to use the resolver warning messages to correct the errors in the resolver setup file.
When the errors are corrected, the network operator needs to issue a MODIFY RESOLVER,REFRESH,SETUP=setup_file command to correct the resolver configuration.

Reference information

For more information about the resolver, see "Customizing the resolver" in z/OS Communications Server: IP Configuration Guide.