NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.

Forum Discussion

kbrumbaugh's avatar
kbrumbaugh
Aspirant
Jul 09, 2024

RBR750 Local NAT Loopback Not Working

I am having issues with NAT Loopback not working with my RBR750 when accessing a resource on my local LAN. I've reviewed this thread (Orbi NAT Hairpinning/Loopback Not Working - NETGEAR Communities)...
CrimpOn's avatar
CrimpOn
Guru - Experienced User
Jul 13, 2024

Might be useful to know what firmware is currently installed on the 750 router.

Message 1 mentioned firmware 4.6.14.3

Message 5 mentioned "will update firmware tonight"

But, I do not see in the conversation where that was done (or not). Did I miss it?

 

Would very much like to look at the data packets between the router and the Synology when a device attempts to connect to port 5001.  That would be a major undertaking (sigh) involving

  • Starting packet capture on the debug page.
  • Attempting to connect. (I would do a web http (port 80), web https (port 443), and then a management connection (port 5001).
  • Save the packet capture.
  • On the computer, open the debug zip file and extract lan.pcap
  • Save lan.pcap somewhere. (I do not think the forum software allows binary or zip files to be attached to messages)
  • Send a link to this file, either on this conversation or a private message.

 

CrimpOn's avatar
CrimpOn
Guru - Experienced User
Jul 14, 2024

(sigh) This is so tedious.  Posts are deleted before I get around to answering them.

 

I manually installed firmware v4.6.14.3 on the RBR750 and performed the NAT-loopback experiment again:

  • Ports 5000 and 5001 forwarded to a computer on the RBR750 LAN at 10.0.0.2
  • Start Rebex web server on the computer, listening to ports 5000 and 5001
  • Connect Chromebook to the RBR750 WiFi
  • Open Chrome web browser to the WAN IP of the RBR750 (192.168.1.71 with ports 5000 and 5001).
    Both ports forward to the web server as they did on the most recent firmware.
  • On a computer on the primary network, open a web server to 192.168.1.71. Both ports 5000 and 5001 connect to the web server on the computer attached to the RBR750.

Only about 20 minutes wasted.  Not as much time as I spent messing up today's Sudoku in the newspaper.

 

My conclusion: NAT hair-pinning (loopback) behaves exactly the same way on the RBR750 using firmware v4.6.14.2 as it does using firmware v7.2.6.31

 

I remain convinced the issue is related to whatever Synology is doing when it connects on port 5001.