Port Forwarding Intermittently Fails on RAXE500

There are two parts to connecting from the internet to resources on the local network:

• Forwarding specific ports to specific devices (and ports) on the local network, and
• Setting up a mechanism to ensure that external users are attempting to connect to the public IP address of the router. (Although external devices could simply include the public IP address in their configuration, the most common mechanism is to subscribe to a Dynamic DNS service (DDNS) which translates a URL into the current public IP address.

If the public IP address is dynamic, then the router has to inform the DDNS service when the public IP address changes.  Because each DDNS service uses their own protocol for updating their DNS database, Netgear has included code in the router for specific providers.  (My Orbi, for example, can use DDNS from Netgear, No-IP.com, and Dyn.com.)

What this appears to be is that the ISP has changed the public IP assigned to this RAXE500 and the DDNS database had not been updated when the remote connection was attempted.  (Or, perhaps, the remote device had cached the previous IP address and was attempting to connect to the wrong public IP address.)

The next time a remote device cannot connect to the local network, it might be worthwhile to record the public IP address that it is attempting to reach.  On Windows, for example, do a nslookup for the URL. (on the remote machine)

The router log file should contain entries every time the DDNS service is update.  Something similar to this:

[Dynamic DNS] host name CrimpOnNet registration successful, Wednesday, Dec 11,2024 23:12:58