The resolver uses the IPv4-unique search order for sitename information when the resolver setup statement NOCOMMONSEARCH is specified (or left to default), and either the:
If the COMMONSEARCH statement is specified, see IPv6/common search order, where the resolver can use IPNODES to locate sitenames.
The resolver uses the IPv4-unique search order for sitename information unconditionally for getnetbyname API calls.
The IPv4-unique search order for sitename information is as follows. The search ends at the first file found:
The value of the environment variable is the name of the MVS™ data set that contains the sitename information. This data set is created by the TSO MAKESITE command.
userid is the user ID that is associated with the current security environment (address space or task/thread).
hlq represents the value of the DATASETPREFIX statement specified in the base resolver configuration file (if found); otherwise, hlq is TCPIP by default.