as a started task. Setting this environment variable is the equivalent of the TCPIPJOBNAME/TCPIPUSERID configuration keywords within the IBM TCPIP.DATA file. If the default value for the TCP/IP stack name is not specified, the value is the first TCP/IP stack that is defined to the system.
For information about setting TCPIPMCH, see Configuring SAS To Use the IBM z/OS Name Resolver.
A SAS data set that is referred to as the TKMVSENV data set file can be used to specify the SAS environment variables. If you use SAS environment variables, you must allocate the TKMVSENV DD in the JCL or CLIST that executes SAS 9.2.
For example, here are the allocation statements for the data set SAS.DATA.TKMVSENV, which contains the desired environment variable information:
Note: Line numbering in the TKMVSENV data set must be disabled.
Each logical record contains an environment variable assignment in this format:
|TCP/IP Name Resolver Configuration|
A name resolver is a set of routines that acts as a client on behalf of an application to read a local host file or to access one or more domain name servers (DNS) for name-to-address or address-to-name resolution. Name resolution occurs by calling the name resolver functions getnameinfo() and getaddrinfo() .
A name resolver must be configured for each host. Here are the locations for UNIX configuration files:
contains the local host configuration data.
contains the DNS domain name and the name servers' IP addresses.
contains the service configuration data.
Starting with z/OS V1R4, IBM introduced support for Internet Protocol Version 6 (IPv6), which is the successor to the Internet Protocol Version 4 (IPv4). In order to support IPv6, new USS BPX calls for the IBM name resolver were introduced to implement the protocol-independent resolver functions that are described in the RFC 3493 specification. Here is a list of the IBM name resolver functions that are supported in IPv6 and IPv4:
When the IBM z/OS Name Resolver is started, it reads the IBM configuration file that is pointed to by the DD statement SETUP, which can contain the following SETUP directives:
COMMONSEARCH | NOCOMMONSEARCH
Note: The most important SETUP directives are GLOBALTCPIPDATA and DEFAULTTCPIPDATA.
identifies a global TCPIP.DATA file. Any TCPIP.DATA directive that is specified in this file are system-wide and cannot be overridden by a local TCPIP.DATA file.
identifies a default TCPIP.DATA file, which overrides the TCPIP.DATA file that is named TCPIP.TCPIP.DATA.
If a GLOBALTCPIPDATA statement is located in the resolver setup file, the IBM z/OS Name Resolver reads any name resolver directives that are located in this global TCPIP.DATA file. The IBM z/OS Name Resolver then searches for a local TCPIP.DATA file in this order:
RESOLVER_CONFIG environment variable
DEFAULTTCPIPDATA value (if specified in the z/OS Name Resolver setup file)
Here are some useful IBM z/OS Name Resolver Server directives:
changes the order in which name resolution is performed between a DNS name server and a local hosts file. Using the LOOKUP directive, you can specify DNS only, LOCAL only, DNS LOCAL, or LOCAL DNS. By default, a DNS name server is queried first. If DNS fails, then DNS LOCAL is used.
specifies a search of up to six domains, in the specified order. The first domain name that is specified is used as the value for DOMAINORIGIN. If both the SEARCH and DOMAINORIGIN statements are specified, the one that appears last is used.
specifies up to four IP addresses to use for a specific host. If DNS returns more than one IP address for a host, SORTLIST can use search masks to sort and identify which IP address the resolver returns.
specifies that for a domain name that contains n or more periods (.), the resolver should look up the name as is before applying the DOMAINORIGIN or SEARCH statement settings. The range of n is 1 to 15. The default is 2.
For complete information about these directives, see the IBM documentation z/OS IP Configuration Guide and IP Configuration Reference.
SAS 9.2 uses the IBM z/OS Name Resolver by default. No configuration is