Hello,

I created this thread in order to help people who intend to use freedns(dot)afraid(dot)org to reach their local network. @Hoamboy 's answer on this issue helped me a lot to solve the issue however isn't solely enough for this particular DDNS service. I also benefited from the explanation in Afraid(dot)org.

The only thing that triggers DDNS to update your WAN IP in Afraid's system is the "Direct URL" to be accessed by ANY device with that particular WAN IP. You can enter the URL in browser and check to verify. That means you don't need to enter username, password nor domain name correctly in router. The only thing you need to fill correctly is "Update URL" because the "Direct URL" that Afraid provides contains all the information it needs in order to update WAN IP. However router rejects savings changes when you paste Direct URL provided as it is. Here is how you should edit Direct URL in order your router would accept:

For the router, I put for all "[USERNAME],[PASSWORD],[DOMAIN]" inside the URL and for Afraid, I put all of them before "@" because it doesn't affect anything. As @Hoamboy said "The update URL needs to be EXACTLY this one (do NOT fill variables with real values!)". The part after "?" will be generated only for you and the one I pasted above is of course randomly modified for security reasons. So only the part in red will be different in your "Update URL" section in router.

I hope this helps anyone.