NAT Loopback Issue

[RMerlin]

This is weird. I've been using an AC68P with Merlin for several weeks and NAT Loopback was working with no problem. A few days ago, it suddenly stopped working. The URL I was trying to reach is a web page hosted on a server on my home LAN.

After spending a few hours trying to diagnose the problem, I found this thread. I switched loopback from Merlin to Asus, as Merlin suggested and that fixed it. I'm just really curious why it worked without an issue for weeks before suddenly not working???

Something caused your router's firewall to get itself reconfigured, without reapplying the firewall rules related to the NAT loopback. This is a known limitation of my loopback method, as services such as Aiprotection can potentially reconfigure the firewall without notifying the rest of the firmware (and so making it impossible to reapply the necessary rules). Usually, a simple reboot or a restart of the firewall subsystem would fix it.

 

[GG7]

If you are not running your own web server and such, would it make more sense to DISABLE the NAT Loopback feature? I am running the TrendMicro stuff on my 68U vB1 and was wondering what to do about this setting.

It is defaulted to MERLIN, but not really knowing if I even need it on or not, brought me to this thread and my question.

Thanks in advance!

 

[Antonin Perrot-Audet]

Hello on my asus 56U (380.57) got the same problem (nat loopback stopped working). Tried fm update but no change. Got it to work by changing loopback from "merlin" to "asus".

 

[Therion87]

Is Merlin perfered to use on an ARM router if you turn off all the TrendMicro stuff. Or will there still be issues?

 

[maghuro]

I know this is a very old thread, but I came to it via search.
Where the NAT Loopback feature? I really need it.
Or has it been deprecated and removed?

 

[RMerlin]

I know this is a very old thread, but I came to it via search.
Where the NAT Loopback feature? I really need it.
Or has it been deprecated and removed?

It's built-in the firewall rules.

 

[maghuro]

It's built-in the firewall rules.

So maybe it doesn't work good on double nat

 

[RMerlin]

So maybe it doesn't work good on double nat

That's expected. The idea of the NAT loopback is for a router to accept LAN connections to its WAN interface. If there is a second firewall between the two, then it will interfere.

 

[maghuro]

That's expected. The idea of the NAT loopback is for a router to accept LAN connections to its WAN interface. If there is a second firewall between the two, then it will interfere.

Yep, i see. Understood!

Thanks Merlin