LQ Link-Member Connects to LQ Link-Master then disconnects or Assignments screen shows "Offline"

Problem

You have done all the necessary network configurations and can connect to the LQ Link-Master but LQ Link-Member sitting behind firewall appears to connect for a short while before disconnecting from LQ Link-Master in remote location or the remote LQ shows red in the Assignments page and can’t be accessed.

You have ensured that the required ports on the LQ Link-Master are reachable (port-forwarded if necessary).

TCP 80
TCP 443 (if Force-HTTPS enabled)
TCP/UDP 655

If in doubt, please look at the LQ-SERIES USER GUIDE (Page 70 onwards) for more information.

Solution

Either the Link Master or Link Member (or both) have an IP conflict or the external port is incorrect.

Checklist:

Check that the configuration is correct for both LQs:
1. If using the public internet check that the ports used (defaults to 80/655) are open using Open Port Check Tool - Test Port Forwarding on Your Router or similar.
2. If using the default ports, make sure that External Connectivity > External Port is “Not Set”
3. Check that routing is set to Internet/Public NAT if using the internet
Check the LQs have unique IP addresses:
1. On the local network, start a ping (using -t on Windows to keep pinging) to the LQ
2. From the Maintenance window, request an LQ reboot
3. If the ping does not fail for up to a minute as the LQ resets, there’s likely a duplicate using that IP address.
If using an External Address, set the port to 655 unless there’s a good reason not to.

Ensuring good network hygiene goes a long way, for example, like keeping an overview of IP Address assignments on the network.