Dynamic DNS help please.

[ianmc]

Hi all
I have a basic linode VPS with pihole, openvpn server & nginx reverse proxy.
The purpose is  to access resources over the vpn in my home network, most important for me is jellyfin streaming.
Also to block ads & tracking through pihole.

So I connect the phone to the vpn, connect through it to  my virtual machine on a server at home (with jellyfin installed)
It works just fine, but with some public wifi, it seems to block VPNs.

So what I was looking to do. Setup a dynamic DNS domain name through one of the free providers for my router at home.
Open a port*, specifically 433 TCP as blocking that in any public wifi is likely a big problem.
Setup the appropriate certificates, and connect & stream.

Doing what I described above it nothing exceptional.

The next part is to setup another domain name for my phone, again with a free DDNS service..
It is possible with this:
https://apkpure.com/dynamic-dns-client/org.l6n.dyndns

*Once done, I want the port open ONLY to the IP of my phone.
So how do I periodically lookup the IP of my phone domain name, and open up the port (433) for the IP of the phone only.
If the IP changes, then obviously the old one is re-blocked.

The purpose of this is to save money on my phone data usage.   I am not interested in having a VPN server hosted at home, as the ISP can be flakey sometimes, oh and my upload speeds suck.


Edit:  I am not interested in using anything like cloudflare tunnels . It is not useful for streaming. Oh as for say streaming with plex, I do not wish to sue it as you require an account and dubious privacy.

Pointers appreciated.

Thanks

 
The purpose of this is to save money on my phone data.

[Maurice]

You can create a firewall host alias containing the DDNS name of your phone, then set this alias as the source in the firewall rule and / or port forward rule. The alias resolve interval can be configured in the advanced firewall settings.

Cheers
Maurice