HOSTNAME


   .-HOSTNAME--=--value_of_hostname_start_option-.   
>>-+---------------------------------------------+-------------><
   '-HOSTNAME--=--fully_qualified_hostname-------'

statements:

GROUP

dependencies:

Enterprise Extender Connections only

Specifies the host name associated with the local TCP/IP stack to be used for Enterprise Extender connections utilizing this GROUP definition. The HOSTNAME you code should be a fully qualified TCP/IP domain name, up to 64 characters long. The HOSTNAME you code will be used to acquire, through DNS name-to-address resolution, the static VIPA address which other Enterprise Extender nodes will use in order to communicate with this host using the Enterprise Extender connection.

HOSTNAME can be used as an alternative to specifying an address explicitly using IPADDR. The benefit to using HOSTNAME, versus IPADDR, is that remote nodes attempting to establish EE connections to this host can perform name-to-address resolution on hostname, which they receive in the APPN session setup flows, and acquire either the static VIPA address (if no address translation is required) or a network address translation (NAT) address that will ultimately get them to the correct static VIPA address (if network address translation is employed). The downside of using HOSTNAME is that additional DNS definition and coordination might be required to get the correct resolution in all domains. The value of hostname can be resolved to either an IPv4 address or an IPv6 address, but it is strongly advised that a hostname resolve to a single static VIPA address, to avoid complications during EE connection establishment.

Specifying the HOSTNAME or IPADDR operand on the Enterprise Extender GROUP definition statement is necessary when your Enterprise Extender configuration requires the use of multiple static VIPAs. The HOSTNAME may also be defined as a VTAM® start option. If the HOSTNAME operand is not specified on the Enterprise Extender GROUP definition statement, it will default to the value of the HOSTNAME start option, unless IPADDR is coded explicitly on the GROUP statement. When the IPADDR operand is present on the GROUP definition statement, the sift-down effect of the HOSTNAME start option is ignored.

Note:

If IPADDR or HOSTNAME is specified on any GROUP definition statement within the Enterprise Extender (XCA) definition, then one of those two operands must be specified on all Enterprise Extender GROUP definition statements (or defaulted from the VTAM start options).
The static VIPA addresses acquired by the way of resolving hostname are validated by TCP/IP during port activation. All static VIPA addresses defined must pass TCP/IP validation prior to the Enterprise Extender connection being available for use.
The fullly_qualified_hostname may be up to 64 characters in length. See z/OS Communications Server: SNA Network Implementation Guide for HOSTNAME length considerations.
The TCPNAME start option is required in a CINET environment if any of the following conditions exist:
- The IPADDR parameter is specified on any of the Enterprise Extender XCA major node GROUP definition statements.
- The HOSTNAME parameter is specified on any of the Enterprise Extender XCA major node GROUP definition statements.
- The HOSTNAME keyword is specified as a VTAM start option.
If OMVS is not initialized at Enterprise Extender line activation, a Common INET environment is assumed.
See z/OS Communications Server: IP Configuration Guide for information about UNIX Systems Services security considerations and required security definitions.