Solved GT-AXE16000 port forwarding for Synology NAS

[B-dog66]

Hi all,

I have a Synology DS220+ and it's setup with DDNS, done all the port forwarding rules on the NAS also on my GT-AXE16000.

The first 30-40 minutes is working just fine, I can reach the NAS from everywhere, after is simply not reachable just randomly. I checked if the ports are open, and I found that none of the ports are open.

Till now I tried the following to troubleshoot:

1. First I disabled UPnP because I noticed that when qBitTorrent registering to Use UPnP / NAT-PMP port forwarding instantly breaks the port forwarding rules and none of the port forwarding ports work except the qBitTorrent ones
2. With qBitTorrent and UPnP disabled port forwarding works for about 30-40 minutes
3. Reset the router and reconfigure from scratch, no setting restored, didn't help firmware 3004.388.6
4. Flashed the latest original firmware 3.0.0.4_388_24329, same issue
5. I change my router back to my backup one (Netgear R7800 Voxel firmware) setup the port forwarding rules and bang after hours of waiting still no issues to reach the NAS via DDNS.
6. I picked up from my office Synology RT2600AC router and working without issues all the port forwardings.

My question is what I'm doing wrong with my Asus router?

 

[drabisan]

Can't make too much sense of your screen capture. Zooming it in makes is a mess.
I'm using a GT-AXE16000 with latest official firmware and I have absolutely no problems with port forwarding to Synology.
First question is super simple: why do you bother to use Synology's router configuration? That one never worked well enough.

What is Synology's management port? It should be 5000 or 5001 if you're using HTTPS (and that's more than recommended, it's trivial to install a certificate).
Let's say you want to use 16001 internally, that why it looks like you're forwarding 2 external ports to a single port? That's calling for troubles!
Forget about UPNP. Unless it's a must and you know why it's a must, forget about it.

Do a simple port forwarding on Asus' interface. That's just working!
Does your carrier uses dual stack? Both ipv4 and ipv6?

 

[sfx2000]

Till now I tried the following to troubleshoot:

1. First I disabled UPnP because I noticed that when qBitTorrent registering to Use UPnP / NAT-PMP port forwarding instantly breaks the port forwarding rules and none of the port forwarding ports work except the qBitTorrent ones
2. With qBitTorrent and UPnP disabled port forwarding works for about 30-40 minutes

You might be running the routing table off the end - torrents can do that.

Reduce the number of connections there, and life might be better...

 

[B-dog66]

Can't make too much sense of your screen capture. Zooming it in makes is a mess.
I'm using a GT-AXE16000 with latest official firmware and I have absolutely no problems with port forwarding to Synology.
First question is super simple: why do you bother to use Synology's router configuration? That one never worked well enough.

What is Synology's management port? It should be 5000 or 5001 if you're using HTTPS (and that's more than recommended, it's trivial to install a certificate).
Let's say you want to use 16001 internally, that why it looks like you're forwarding 2 external ports to a single port? That's calling for troubles!
Forget about UPNP. Unless it's a must and you know why it's a must, forget about it.

Do a simple port forwarding on Asus' interface. That's just working!
Does your carrier uses dual stack? Both ipv4 and ipv6?

Synology management port is changed to 16001, I check my NAS settings on the office and there it was 12001 and from there it came to change it.

Changed back to Synolgy's original port 5001

I found the issue, it was the Synology's router configuration, my mind it was stuck on the Synology ecosystem, I removed all the port forwarding from the Synology's router configuration and bang magic happens for 30 min and after it's hard to reach my NAS.

Yes my carrier has both ipv4 and ipv6

You might be running the routing table off the end - torrents can do that.

Reduce the number of connections there, and life might be better...

I have 5019 / 300000 - 418 active connection at the moment, I think this is still ok.