.-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.