Hosting NFSv3 behind a firewall

If we try to use the showmount command from the nfsclient, we should be able to list exports on the remote NFS server. The syntax will be as follows:

$ showmount -e 192.168.10.10

The command and the corresponding error are shown in the following screenshot:

At this stage, we can choose from the following options:

• Pack our bags and go home, perhaps it will be better tomorrow

• Google the error

• Debug the error ourselves

Diagnosing NFSv3 issues

Now, Google is often really good at helping us, but you fail to learn fault-finding techniques, so let's opt out of option 3 and install the tcpdump command-line packet analyzer so that we can see what is happening. This can be installed on nfsclient using yum as follows:

$ sudo yum install -y tcpdump

To capture network traffic between the nfsclient and the nfshost and to print port numbers that are being accessed, we can use the following command:

$ sudo tcpdump -nn -i enp0s8 host 192.168.10.10

The options to tcpdump used here...