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IBM AIX: How to force mountd/lockd to use a specific port

Question & Answer


Question

How do I force mountd/lockd to use a specific port on AIX?

Answer

The ports for rpc.mountd and rpc.lockd may be specified using /etc/services. This configuration is not supported with rpc.statd and there are no plans to further enhance rpc.statd. Environments with strong network firewall requirements should consider migration to NFS version 4, which maintains the full protocol over the primary NFS server port 2049. NFSv4 does not require inter-machine communication for rpc.mountd, rpc.lockd, or rpc.statd.

Here is an example of restricting mountd to port 9999 and lockd to port 9998:

# vi /etc/services
mountd 9999/tcp
mountd 9999/udp
lockd 9998/tcp
lockd 9998/udp

# stopsrc -g nfs

# stopsrc -s portmap

# startsrc -s portmap

# startsrc -g nfs

To check which ports are used by mountd and lockd, run this command.
 
# rpcinfo -p

The mountd and statd daemons will now be listening on those ports.

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Document Information

Modified date:
13 March 2025

UID

isg3T1010663

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