Configuring static VIPAs for Enterprise Extender
Defining at least one static VIPA is required by VTAM® to access the IP network. Because VTAM does not move within a sysplex, a dynamic VIPA cannot be used. Enterprise Extender supports the use of multiple static VIPA addresses, and a VIPA address is chosen as follows:
- VTAM uses the IPADDR value specified on the Enterprise Extender XCA major node GROUP definition statement, or the VIPA address obtained when name-to-address resolution is performed on the HOSTNAME value specified on the Enterprise Extender XCA major node GROUP definition statement.
- If the GROUP definition statement specifies neither IPADDR nor HOSTNAME, VTAM uses the static VIPA address specified on the VTAM IPADDR start option, or the static VIPA address returned by the resolver when name-to-address resolution is performed on the value of the VTAM HOSTNAME start option.
- If neither the IPADDR nor the HOSTNAME start option is specified, VTAM uses the first IPv4 static VIPA in the HOME list.
If remote APPN nodes use a host name and not a host address to define the destination of an Enterprise Extender connection, the domain name server must return the VIPA address used by VTAM for the host name. Alternatively, if the Enterprise Extender endpoints are behind a firewall or for another reason require network address translation, the domain name server should return a network address translation (NAT) address. This NAT address should in turn map, on the destination side, to the static VIPA address of the intended target VTAM host.
For more information about using Enterprise Extender, see z/OS Communications Server: SNA Network Implementation Guide.