Access from local network not working after setting up DuckDNS

Configuration
1

Hi,

I’m trying to setup a new HA instance and I’d like to access it via the DuckDNS. I have configured everything and I can access my instance on mysite.duckdns.org.

However, I can only access the instance if I’m not connected to my local network. When accessing from local network I get an error and possibility to retry, but it will not connect. When using the companion app I get this message: The home assistant hostname certificate mismatch, please review the HA certificate or the connection settings and try again.

When I try to access the HA from local network via the IP address it still doesn’t work.

I have double checked the setup and compared it to the one I have which is working and everything looks fine. The only difference is in the routers, so I suspect something might be wrong with port forwarding configuration.

I’m using Speedport 3 I have configured the port forwarding from 443 to 8123 and I have disabled firewall for the IP address of the HA instance on port 443.

Does anyone have any idea what might be wrong in the configuration?

2

When you installed DuckDNS you also installed LetsEncrypt so that you could use SSL over the internet (end to end encryption) to protect your data.

So you need to access https://<ip_address>:8123 not http on your local network.

You will also have to add a security exception to your web browser as the SSL certificate is for your DuckDNS domain, not your mdns address or ip address.

3

Further to what Tom said, I don’t think you can make that “exception” in the companion apps, so you will need to use the duckdns name, there.

If you know your way, you can redirect the duckdns name in the DNS setup of your lan, to avoid going through internet, but that’s another story.

4

I run home assistant on a proxmox VM, and have Nginx proxy manager running in an LXC. Was really easy to setup, and lets me use SSL externally, whilst keeping it unencrypted on the local network.

If you have SSL on, on your local network, I’m guessing any wifi devices you have connected will break and need reconfiguring ?

I also heard that for some low power (cpu) devices, that the SSL overhead can be burdensome, but I’m not sure if thats true or not.

5

Hey,

thank you for your reply. That is the solution.

Do you know how I can set up the installation so that I always access the HA instance via duckdns address regardless if I’m on local network or outside of it?

6

In the app? Just don’t specify an internal address?