I have a NAS box setup at a different location than our company. The idea was to use it as offsite backup. When the NAS box was on our LAN we had no issues mounting the NFS shares. Once we moved it to the offsite location we are unable to talk to it.

So far I have forwarded ports (tcp and upd): 2049, 111, 1110, 4045

Every command such as rpcbind, showmount and mount itself all report connection timed out.

It has become increasingly hard to determine where I am being firewalled. Can anyone point out some tips. What ports do I need to open at the offsite location and which ports need to be forwarded at our main location?

  • Mind tracerouteing to it, and pasting the report here - ( or rather, using that to determine where you're being firewalled ;) )?
    – user98085
    Jan 15, 2013 at 19:46
  • 2
    Do you use static ports for NFS?
    – dchirikov
    Jan 15, 2013 at 19:49
  • I've updated with traceroute. The NAS is somewhat primitive so I can't configure much on it. A nmap of the NAS shows which ports are open (2049 being one of them). Do I setup static ports for the NFS on the side trying to mount it? I found this article which might help shed some light (novell.com/support/kb/doc.php?id=7000524).
    – Halsafar
    Jan 15, 2013 at 19:57
  • I added mount -v output for a failed attempt to mount the NFS.
    – Halsafar
    Jan 15, 2013 at 20:36
  • 2
    Do you really want to transfer your important backup via an unencrypted connection through the internet? Jan 16, 2013 at 7:52

3 Answers 3


Aside from hunting down every single ports opened/required by NFS, consider setting up a VPN tunnel between your firewall since you are in control of both ends. Then mount your nfs through the tunnel, that will save you a lot of trouble and firewall(and NAT) configuration.

NFS server behind firwall require special setup on the server itself, however I doubt you can do it with a NAS device. Following is a guild from RedHat https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/s2-nfs-nfs-firewall-config.html

I think vpn tunnel is really your best choice if not the only choice.

  • The reason I marked this as the answer is two fold. First VPN is really the best way to set this up. I flashed DD-WRT onto the router at the offsite location and then setup OpenVPN. Second, the method I was trying to setup is totally unencrypted (as pointed out by Philipp Wendler in OP). So anyone ending up here attempting the same, just setup a VPN and be done with it.
    – Halsafar
    Jan 18, 2013 at 20:47

Assuming you are in control of the firewalls both on your local site and the remote site (pertaining to your own network that is) did you try temporarily dropping the firewalls on both sides ? This might very well be a port blocking issue, originating from your link provider.

  • I am in control of both sides. The only firewall the NAS is behind at the offsite location is the router it is plugged into. So a pseudo firewall. I could try DMZ`n the NAS box to see if that helps? Onsite location we have full control over as well. The linux box trying to mount the NFS I've disabled ufw firewall but it is also behind a router... I'm quite positive this is a port blocking issue. I'm just stumped on which ports need to be open on both sides.
    – Halsafar
    Jan 15, 2013 at 20:30

On NFS client OS you can run:

showmount -e your_nfs_server_ip

At the same time open another terminal to same machine and run:

netstat -nputw

Then you will see outgoing ports.

In my case helped adding port 55493 to router NAT

  • Another idea is to set DMZ to NFS IP Dec 9, 2016 at 12:11

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