Can't access Synology using DDNS domain

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Can't access Synology using DDNS domain

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Last edited:
Hi

On my NAS I setup a DDNS to use when connecting with OpenVPN.

However, when I am using the VPN if I give that address in my browser (https://ddnsname.provider.me:40XX) nothing happen.

The only way to access DSM is by using the IP address of the LAN port 192.168.XXX:40XX

Is that normal? I check port-forwarding and the only port I am forwarding is the one used by the VPN
 
73
13
OpenVPN tends to be on 1194 from my experience. Where did you get the 40XX? Is that you setting access to the DSM web interface? Do you have your firewall enabled?
 
105
3
NAS
DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
OpenVPN tends to be on 1194 from my experience. Where did you get the 40XX? Is that you setting access to the DSM web interface? Do you have your firewall enabled?
Hi Akira, yes the 40XX is to access the DSM via web interface port not the VPN.

For Firewall you mean the one on my Syno? Yes is activated ...
 
105
3
NAS
DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
Ok, in the firewall on the Syno, you need to allow OpenVPN to access it.
https://ddnsname.provider.me:1194 is what you need to use to connect to the VPN.
Also you need to make sure your router is port forwarding 1194 to your NAS.
In the firewall settings the VPN port is set properly. As well the port forwarding of the router. In fact I can connect to my Synology via OpenVPN and access files via SMB.

What I cannot do is access the DSM via DDNS over the browser like this https://ddnsname.provider.me:40XX when I am connect with OpenVPN.

If I want to access my DSM via Browser, when connected through OpenVPN, I always have to type-in the IP address 192.XXX.X.XXX
 
73
13
Ah, right... Sorry misunderstood.. Let me check my end (Though I'm using OpenVPN via a docker).
Nope, mine routes perfectly.. Do you have internet access when you've connected via OpenVPN?
 
105
3
NAS
DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
Ah, right... Sorry misunderstood.. Let me check my end (Though I'm using OpenVPN via a docker).
Nope, mine routes perfectly.. Do you have internet access when you've connected via OpenVPN?
Yep I can access the internet normally.

Can be a reason that my router is not port-forwarding the DSM port?
 
73
13
If it works without the OpenVPN connection. Then I don't think so.
What response do you get if you ping ddnsname.provider.me when the VPN is up?
If that comes back with a response what about a tracert?
Do you have a DNS rewrite internally?
In the firewall on the DSM is the VPN subnet given permission to access the DSM portal?
What happens if you use CTRL F5 to refresh internet pages or the DSM web portal?
What exact error do you get when trying to access the portal?
Are you sure the internet is working properly and the pages aren't just cached?
(Just trying to exhaust all possibilities)

I have to admit, I've configured all of this using:
SWAG
cloudflareddns
openvpn-as

rather than using the Synology UI.
 

Rusty

Moderator
NAS Support
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Is that normal?
If your router does not support NAT loopback this might not work, correct. The same should happen if you are inside your NAS LAN and try to access your NAS using its DDNS address.

If your router doesn't know how to handle this it will drop out. guessing when you don't have VPN active this URL works fine (with proper port forward)? If so, that means that it's all well, and it all comes down to your router and its support/configuration for NAT loopback.
 
105
3
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DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
guessing when you don't have VPN active this URL works fine (with proper port forward)?
You mean when I try to connect using the URLand I am not in my local netowrk?

Cannot access it. I guess because I have to forward that port (my DSM port) in order too. Am I right?
 

Rusty

Moderator
NAS Support
3,137
946
www.blackvoid.club
NAS
DS718+, DS918+, 2x RS3614RPxs+
Router
  1. RT1900ac
  2. RT2600ac
  3. MR2200ac
Operating system
  1. macOS
Mobile operating system
  1. iOS
You mean when I try to connect using the URLand I am not in my local netowrk?

Cannot access it. I guess because I have to forward that port (my DSM port) in order too. Am I right?
Correct on both. If you don't have 4xxx published you will not be able to use it without a VPN but looks like once you are in, you cant use it because of a problem with NAT loopback. Either that or your firewall on your NAS is blocking that access somehow.
 
105
3
NAS
DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
Last edited:
Correct on both. If you don't have 4xxx published you will not be able to use it without a VPN but looks like once you are in, you cant use it because of a problem with NAT loopback. Either that or your firewall on your NAS is blocking that access somehow.
I see. I will look into it.

Whats it's really strange to me (because i'm not an expert :p) is that I can connect to DSM with the VPN using the IP address of my NAS LAN but not with the DDNS (URL).

A DDNS and the IP address are not the same thing?
 
105
3
NAS
DS920+
Operating system
  1. macOS
  2. Windows
Mobile operating system
  1. Android
  2. iOS
The same should happen if you are inside your NAS LAN and try to access your NAS using its DDNS address.
So I went to the office and did a test. I tried to connect to the DDNS hostname https://ddns.provider.me and it does not load.

So this means that everything is "normal" I guess.
 

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