Internet Protocol version 6 (IPv6) expands the range of addresses that are available for internet communications. IPv6 extends address sizes from a 32-bit value to a 128-bit value, vastly expanding the number of globally unique addresses that can be assigned. Both the z/OS NFS Client and the z/OS NFS Server support the longer addresses of IPv6, as well as the 32-bit addresses of IPv4 and below. Your network infrastructure must be enabled to use IPv6; if the network does not support IPv6, z/OS NFS will use IPv4 instead.

The z/OS NFS server can use both IPv6 and IPv4 for all NFS protocols.

SMF records for the z/OS NFS server report client IP addresses for both IPv4 and IPv6, with separate address fields for each.

The z/OS Portmapper does not support IPv6. Therefore, when using IPv6 addresses, the z/OS server host must be configured with RPCBIND, not the Portmapper. RPCBIND supports both IPv6 and IPv4. As of z/OS V1R8, Portmapper should only be used for IPv4 only systems. Otherwise, RPCBIND should be used.

Mount handle database (MHDB) records may be affected in the following situation: The zOS NFS server is started in an IPv4 system. Subsequently a restart of the zOS NFS server in an IPv6 system. Then another restart of the zOS NFS server in an IPv4 system. This may cause the situation where IPv6 addresses cannot be converted to IPv4 addresses. The MHDB may contain IPv6 addresses that cannot be referenced when running in IPv4 mode. Thus mounts will not be rebuilt properly.