port forwarding: what am I missing?

[Herman Slotenmaker]

done this dozens of times; but seem to be mising something stupid this time.

AC-86U on aimesh with AC-68U. Brand new setup. Merlin 386.1 Trying to open port 31001 to 3101 on my Synology. This worked without problems till I swapped My AC68U by AC86U as the main router last week.

First I thought the apply button was missing. But this seems not to be the case: https://www.snbforums.com/threads/asus-merlin-port-forwarding-apply-button-missing-384-16.64036/

Tried many different settings (firewall on and off; local port blank,...), but the port won't open. Any suggestions?

canyouseeme.org keeps telling mee: Error: I could not see your service on ************ on port (31001)

 

[eibgrad]

Admittedly this is pretty rare, but I have seen cases where the router has been rebooted only to suddenly find the ISP has assigned a *private* IP on the WAN (e.g., CGNAT, which can NOT be port forwarded) rather than a *public* IP. Perhaps because of heavy loading and limited IPv4 addressing at that time. At the very least, it's worth checking. A CGNAT ip would typically start w/ 100.64.x.x. Or it might NOT be CGNAT, but just something in the private IP space generally (10.x.x.x, 192.168.x.x, 172.16.x.x).

 

[dave14305]

The default subnet for an 86U is 192.168.50.0. Did you set it back to 192.168.1.0 when you swapped routers?

 

[Herman Slotenmaker]

Hmm, I'm not quite sure I understand both answers. But we're might be onto something.

I believe it shouldn't say 192.168.0.160 by WAN IP...

 

[ColinTaylor]

I believe it shouldn't say 192.168.0.160 by WAN IP...

Correct. That is not a public IP address so that suggests that your Asus' WAN port is connected to another router. What is that upstream device? Perhaps it is a modem/router combi that was previous configured in "bridge mode" but has been reset to "router mode".

 

[Herman Slotenmaker]

Correct. That is not a public IP address so that suggests that your Asus' WAN port is connected to another router. What is that upstream device? Perhaps it is a modem/router combi that was previous configured in "bridge mode" but has been reset to "router mode".

100 points!

The router/modem was still bridged to my ASUS AC-68Us MAC-address...completely forgot about setting the bridging..

Thank you all