Cannot establish a network connection on the port

[stijn]

I’ve been trying to connect to my desktop (Ubuntu 21.04) from a remote location using NoMachine unfortunately to no avail.

Connecting while my laptop (Ubuntu 21.04) and desktop are on the same network is not an issue.

To connect I tried the third listed IP address from the available options (NX protocol) while using the port as instructed in the NoMachine instructions. The error message I get states that it refused to establish a network connection on the port. Please verify that NoMachine is correctly installed and listening on the port where you are trying to connect, and that incoming traffic is not being blocked by a firewall or NAT.

I did check my router settings, and also added a forwarding port setting my local IP-address of my desktop and the specified port. UPNP is enabled on my router.

I have no idea how to check whether incoming traffic is blocked by a firewall or NAT.

Any help would be greatly appreciated!

[Carin]

Hi Stijn,

It looks like this topic dealt with a similar case: https://forums.nomachine.com/topic/cant-connect-from-outside-of-network

Please take a look at it and let us know it helps. 😉

[stijn]

Hi Carin,

Thank you for your reply.

I already tried port forwarding and used the same strategy as written in the post you mentioned, which did not resolve the issue for me. Also, my IP address is static and does appear the same across different websites and the application.

[Carin]

Can you check if the external IP in NoMachine is the same as on this page https://www.whatismyip.com/ ? If it’s the case then it should work.

If it doesn’t work, please check the rules for your router’s firewall.

If the IP is a different one, it can mean that you have a double NAT router.

It would also be helpful if you could check the port forwarding of some different services like SSH.

[stijn]

Hi Carin,

The IP address listed is the same as the address listed on that website.

Which settings in the firewall should be adjusted?

Thanks,

Stijn

[Carin]

Hi stijn,

Are you sure that you are connecting to the correct IP and Port?
Please execute this command sudo /etc/NX/nxserver --upnpstatus on the sever side and connect to IP and Port which are listed in the line starting with:  NX port 4000 mapped to:

If the problem appears please enable debug, restart nxserver (sudo /etc/NX/nxserver --restart) and execute the commands below:

sudo /etc/NX/nxserver –upnpstatus
sudo /etc/NX/nxserver –upnpmap

Send the logs to forum[at]nomachine[dot]com, making sure you add the title of the topic in your email subject.
In this article, you can find more instructions on how to enable and collect debug logs automatically: https://www.nomachine.com/DT10O00162.

Can you also tell us your router model?

[stijn]

Hi Carin,

I forwarded the generated logs.

I tried connecting to it and also changing the port, but yes both the IP and Port are those as listed in the –upnpstatus command.

Router model is the one that was provided with my internet contract: https://fizz.ca/en/wi-fi-technologies, which has model name CODA-4680.

Thank you for your help,

Stijn

 

[Carin]

Hi stijn,

Here you can find instructions for your router: https://portforward.com/hitron-technologies/coda-4589-res/

We could not find anything in the logs and we could not see the connection attempt, which indicates a firewall configuration problem.
Did you use the same port in port forwarding as UPnP? (UPnP port you can check in the player welcome screen on with sudo /etc/NX/nxserver--upnpstatus command)

Can you send us screenshots from the router port forwarding setup? Please send them via email to forum[at]nomachine[dot]com adding the title of the topic as the email subject.  Thanks!

[Author]

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