TCP/IP

Ensure that the MTU (Packet Size) is set to the lowest MTU when in a heterogeneous network. For example, if the network is comprised of: 
Ethernet 802.3 (MTU=1492)
Ethernet Version 2 IEEE (MTU=1500)
token ring (MTU=2000)
FDDI (MTU=4000)
CTC (MTU=65527)
CLAW (MTU=4096)
In this example, the lowest MTU is set to 1492 to reduce packet fragmentation. The MTU setting is defined in the TCP/IP profile.

If there are changes to network addressing and the z/OS NFS server is running in NODHCP mode, the following sequence must be performed to correctly process the changes within the NFS server:

  1. Unmount all client mounts
  2. Clear the mount handle database (MHDB)
  3. Stop the z/OS NFS server
  4. Make the necessary changes in the network
  5. Restart the z/OS NFS server.
Parent topic: Environmental checklist