The resolver acts on behalf of programs as a client to perform
the following functions:
- Access name servers to provide name-to-address or address-to-name
resolution
- Allocate and read the TCPIP.DATA file
- Establish TCP/IP stack affinity for certain socket APIs
- Provide protocol and services information
To resolve the query for the requesting program, the resolver uses
information that it obtains from the following sources:
- Available name servers
- The DNS response information that has been cached locally (when
system-wide caching is enabled)
- Local definitions, such as /etc/hosts, /etc/ipnodes, HOSTS.SITEINFO,
HOSTS.ADDRINFO, and ETC.IPNODES
The TCPIP.DATA statements control how (and if) the resolver uses
name servers. For detailed information about TCPIP.DATA configuration statements, see z/OS Communications Server: IP Configuration
Reference.
Requirement: The resolver address space
must be started before any application or TCP/IP stack resolver calls
can occur.