Dynamic addressing

Before z/OS® V1R7, the z/OS NFS client and server were based on the static IP address model to handle all communications with other systems. However, many systems have migrated from the use of static IP addresses to the dynamic host configuration protocol (DHCP). Now, the z/OS NFS server accepts dynamic NFS client IP address changes and properly understands the source of the communication even if the sender's IP address has changed. Since not all customers' environments use dynamic IP addresses, NFS server site attributes have been added to specify whether the NFS server should use the dynamic IP algorithm (dhcp) or the current static IP algorithm (nodhcp). The default is nodhcp, to use the static IP algorithm.

To use dynamic IP addressing, the client must:

Have a constant host name that the NFS server can identify it by.
Dynamically update the authentication DNS (dynamic name server) with new IP addresses whenever they change.
Maintain the TTL (time to live) value that the authentication DNS server specifies to any caching DNS server, based on the frequency with which system IP addresses might change.

If you are using the static IP algorithm (nodhcp) and there are changes to network addressing, the exportfs command will not rebuild the exports list correctly. See TCP/IP for further details.

For more information, see Using dynamic client IP addressing.

The z/OS NFS Server continues to have a static IP address, based on the standard industry practice of assigning static IP addresses to servers.