Can't access DDNS address from behind router

[Ojee]

I've got a RT-AC87U with a DDNS address running provided by Asus. I'm running a NAS behind it with some music on it, and I've got the following problem.

I listen to music from the NAS on my phone, using the DDNS asuscomm address. When I switch from 4G to wireless after coming home, it can't connect to the asuscomm address and just times out. The only way to continue listening is to log out and log back in again using the local network address.

What I'd like is for that transition to be seamless, without having to login in and out again. Is there a way to do that?

 

[ApexRon]

I can be listening to iTunes on my iPhone using a cellular connection and when I get within range of my wifi, iTunes playback will stop. All I have to do is select play and it continues. In my case, iTunes cannot make the transition from cellular data to wifi seamlessly. Though I have not tried, I suspect video streaming is the same. I think the issue is associated with our phones not seamlessly moving TCP or UDP connections between cellular data and wifi data. Phone manufacturers are leaving it up to the app to recover.

 

[Ojee]

Yeah but I have the same problem on my laptop. From behind my router, I can't access the DDNS address, only the internal ip.

 

[ColinTaylor]

What firmware version? Might be the same as this report: https://www.snbforums.com/threads/nat-loopback-missing-rt-ac86u.48525/

 

[Ojee]

Could very well be. I am using the latest Merlin WRT firmware.

 

[ApexRon]

Yeah but I have the same problem on my laptop. From behind my router, I can't access the DDNS address, only the internal ip.

I stand corrected. I just retested iTunes at the current IOS version and the transition was seamless, iTunes continued playing as I moved from cellular data to wifi data.

Let me restate your issue and update:

1. Your music playing is interrupted as you move from cellular data to wifi data
2. Using the URL for your music server, you are unable to connect to your music server

Assumptions:

1. Your router is using internet address assigned by DHCP from your ISP
2. Your router is NOT using NAT
3. DDNS is the method chosen to have a URL point back to the current internet address for your router

Has this ever worked?

 

[ColinTaylor]

Your router is NOT using NAT

I think this statement is a mistake. It would be very unusual if he didn't have NAT enabled on the router.

 

[Ojee]

Assumption 1: correct
Assumption 2: i'm forwarding a port to my NAS for my music server.
Assumption 3: correct.

Has it ever worked? If you are asking if I was ever able to connect to my DDNS address from behind my router, the answer is no. It has only worked on an external connection such as 4G. But I would like it to.

 

[ApexRon]

I think this statement is a mistake. It would be very unusual if he didn't have NAT enabled on the router.

I don't disagree with you but from the router manual section in how to configure DDNS:

"NOTES:
DDNS service will not work under these conditions:
• When the wireless router is using a private IP address (192.168.x.x, 10.x.x.x, or 172.16.x.x), as indicated by a yellow text.x.x, 10.x.x.x, or 172.16.x.x), as indicated by a yellow text.
• The router may be on a network that uses multiple NAT tables."
​

Considering the confusing quote from the manual and the fact that the owner is using Merlin, I can be of no further help.

 

[ColinTaylor]

Has it ever worked? If you are asking if I was ever able to connect to my DDNS address from behind my router, the answer is no. It has only worked on an external connection such as 4G. But I would like it to.

Ah sorry, I thought this was something that used to work but now doesn't. I can't be of any help as I know nothing about your music player or how it works.

 

[Ojee]

Ok but it's not just my music player. I can't access the asuscomm address at all when I'm on my local network. Regardless of what computer I use or service I'm trying to access.

 

[ApexRon]

Ok but it's not just my music player. I can't access the asuscomm address at all when I'm on my local network. Regardless of what computer I use or service I'm trying to access.

If your device is using DHCP DNS address, it could be that the router OS is intercepting the device's DNS lookup request because of DDNS configured on the router. Should that be the case, I am not sure why the router is not allowing the connection. I always recommend that devices use Google DNS, OpenDNS, or others. That said, I am not certain that using an off net DNS would be a fix but I would try it.

Plug in the current ISP assigned IP address into your device's music player and see if you can reach the server using your home WiFi.

 

[Ojee]

I tried using the ISP assigned IP, and that also doesn't work.