tches a system_name remains in effect.
A HOSTNAME statement is ignored under these conditions:
the system_name prefix did not match the VMCF node name
VMCF is unavailable
The system name does not match the MVS name of the system that the TCP/IP stack started under.
Therefore, it is critical that VMCF is running before any TCP/IP stacks are started.
IBM System Name Considerations
The VMCF node name is used as the system_name prefix when processing IBM TCPIP.DATA configuration statements. The VMCF can be configured in two ways:
as a restartable subsystem
If you have configured VMCF as a restartable subsystem, the node name is obtained from the value of the P= parameter in the EZAZSSI started procedure.
as a non-restartable subsystem
If you configured VMCF as a non-restartable subsystem, the node name is specified in the IEFSSNnn member of parmlib.
Note: IBM recommends that the MVS system name be used for the VMCF node name specification.
For details about configuring VMCF, see References.
|TCP/IP Stack Configuration Files|
When a TCP/IP stack is started, the TCP/IP stack reads one or more configuration files that contain statements that define its default behavior. Here are the configuration files:
The following PROFILE.TCPIP statements can restrict the ports that SAS servers can use:
reserves ports for server tasks. The PORT statement specifies only the job names and PROC names that are allowed access to the port.
is the same as PORT parameter but for a range of ports.
defines a list of user IDs that are prohibited from using TCP/IP.
restricts the use of ports 1 to 1023 to specific job names or PROC names that are specified in the PORT or the PORTRANGE statement.
The search order that is used by the IBM TCP/IP stack to locate PROFILE.TCPIP involves both explicit and dynamic data-set allocation, as follows:
//PROFILE DD DSN=
Note: IBM recommends explicitly specifying the PROFILE DD statement in the TCPIPROC JCL. When the PROFILE DD statement is specified, no dynamic allocation is performed.
SAS does not access the PROFILE.TCPIP file directly. However, because this file is used to configure the IBM TCP/IP stack, the statements in this file can have an indirect effect on how SAS operates.
The TCPIP.DATA file contains the following statements that are used to configure the IBM TCP/IP stack and Communication Server applications.
specifies the member name of the procedure that is used to start the TCPIP address space, which is the TCP/IP stack name.
is used by the TCP/IP stack to determine its host name.
specifies the name of the domain origin, which is appended to the host name to form the fully qualified domain name of the host.
is a high-level qualifier (hlq) for the dynamic allocation of data sets in IBM TCP/IP servers and clients.
For details about the IBM TCPIP.DATA statements, see References.
The IBM TCP/IP stack and the IBM Communication Server applications, including the IBM z/OS Resolver, use the following search order to locate the data set that contains the TCPIP.DATA configuration statements:
GLOBALTCPIPDATA value (z/OS 1.2 and later releases)
RESOLVER_CONFIG environment variable
DEFAULTTCPIPDATA value (z/OS 1.2 and later releases)
There is usually a one-to-correspondence between a TCP/IP stack and its host name. The host name is obtained using the gethostname() function. However, for systems that run using multiple TCP/IP stacks, the identity of the stack's host name is ambiguous. Here is the process for resolving the host name for a multiple TCP/IP stack system:
The process that calls gethostname() might be bound to a specific TCP/IP stack. The binding is referred to as TCP/IP stack affinity. If affinity to a specific TCP/IP stack has been established, the gethostname() function returns the host name for the specific stack.
There are several methods of setting the TCP/IP stack affinity. SAS uses the UNIX System Services call, pfsctl(BPX1PCT). For details, see Determining SAS TCP/IP Stack Affinity.
Otherwise, the process returns the host name of the default TCP/IP stack. For details about the default stack, see Co