How to fix "mountd: refused mount request: unmatched host"

Error:

On Client (192.169.32.17)
# mount 192.169.32.10:/export/home/deepak /mnt
mount.nfs: access denied by server while mounting 192.169.32.10:/export/home/deepak

On NFS Server (192.169.32.10)
# tail -n 1 /var/log/messages
Sep 13 00:00:32 cc01-nds-ins rpc.mountd[29613]: refused mount request from 192.169.32.17 for /export/home/deepak (/export/home/deepak): unmatched host

Solution:

This error is occurring because the NFS server is unaware of the client network attempting to access the NFS shares.

As for my case below are the list of directories which are shared using NFS server

As you see the directories are shared for 10.10.10.0/255.0.0.0 subnet while my client server IP is in a different subnet 192.169.32.0/255.255.255.224

So I need to add this subnet in my exports share

On NFS Server (192.169.32.10)

Add a new line in /etc/exports file as shown below
# vi /etc/exports
/export/home/deepak 192.169.32.0/255.255.255.224(ro,sync,no_subtree_check)
Refresh the share
# exportfs -ra
List the updated share information
Let us re-attempt to access the NFS share from our client

On Client (192.169.32.17)

# mount -t nfs 192.169.32.10:/export/home/deepak /mnt
# mount | grep export
192.169.32.10:/export/home/deepak on /mnt type nfs (rw,addr=192.169.32.10)

I hope this tutorial was helpful.