NFS Connection Cheat Sheet

The nfs-common package on Debian and Ubuntu, and the nfs-utils package on RHEL and CentOS, provide most NFS client and server utilities.

There are two different things to check:

• Mounted NFS filesystems: configured and currently mounted NFS shares.
• Active network connections: connections that currently exist between the client and server.

Client Commands

List Mounted NFS Filesystems

Use findmnt to list NFS and NFSv4 mounts:

findmnt -t nfs,nfs4

Other ways to inspect the mounts are:

mount | grep -E ' type nfs| type nfs4'
cat /proc/mounts | grep -E ' nfs4? '

Show NFS Mount Details

nfsstat -m displays NFS-specific information for each mounted filesystem, including mount options and server details:

nfsstat -m

Show NFS Client Statistics

Use the following command to display client-side RPC and NFS statistics:

nfsstat -c

Check Active NFS Connections

NFS commonly uses TCP port 2049. Use ss to check for active connections:

ss -tnp | grep ':2049'

This shows live network connections, not just mount entries. A mounted filesystem can remain configured even when there is no currently active TCP connection.

Server Commands

List Exported Directories

Show the server’s active exports and their options:

exportfs -v

List Clients Reported by mountd

Use showmount to list clients and directories known to the mount daemon:

showmount -a
showmount -d

showmount may not show every NFSv4 client because NFSv4 does not always use mountd in the same way as NFSv2 and NFSv3.

Show Server-Side NFS Statistics

nfsstat -s

Check Active Client Connections

On the server, inspect connections to TCP port 2049:

ss -tnp | grep ':2049'

Some Linux systems also expose NFSv4 client state through /proc:

ls /proc/fs/nfsd/clients

Quick Reference

# Client: list mounted NFS filesystems
findmnt -t nfs,nfs4

# Client: show mount options and NFS details
nfsstat -m

# Client or server: show NFS statistics
nfsstat -c       # client statistics
nfsstat -s       # server statistics

# Client or server: show active NFS TCP connections
ss -tnp | grep ':2049'

# Server: show exports
exportfs -v

# Server: show mountd clients and directories
showmount -a
showmount -d