NFS port ranges

Edit online

The NFS_PORT_RANGE environment variable can be used to limit the source port of network calls the client makes to the server.

If used, this environment variable must be added to the /etc/environment file. The format of the environment variable is as follows:

NFS_PORT_RANGE=udp[4000-5000]:tcp[7000-8000]

In this example, UDP packets sent by the client have a source port in the range 4000 - 5000, and TCP connections have a source port in the range 7000 - 8000. To avoid port reuse problems, the port numbers that are specified in this range must not be used as fixed port numbers for any of the Network File System (NFS) daemons in the /etc/services file.