I'm pretty new to selfhosting and homelabs, and I would appreciate a simple-worded explanation here. Details are always welcome!
So, I have a home network with a dynamic external IP address. I already have my Synology NAS exposed to the Internet with DDNS - this was done using the interface, so didn't require much technical knowledge.
Now, I would like to add another server (currently testing with Raspberry Pi) in the same LAN that would also be externally reachable, either through a subdomain (preferable), or through specific ports. How do I go about it?
P.S. Apparently, what I've tried on the router does work, it's just that my NAS was sitting in the DMZ. Now it works!
You need a reserve proxy. That's a piece of software that takes the requests and puts them toward the correct endpoint.
You need to create port forwards in the router and direct 80 and 443 (or whatever you're using) toward the host of the reverse proxy and that is listening to on those ports. If it recognized the requests are for nas.your.domain, it will forward the requests to the NAS.
Common reverse proxies are nginx or caddy. You can install it on your raspberry, it doesn't need it's own device.
If you don't want that, you can create different port forwards on your router (e.g. 8080 and 8443 to the Raspi) and configure your service on the Raspi corresponding. But it doesn't scale well and you'd need to call everything with the port and the reverse proxy is the usual solution.
There's an issue with that first part. Do I configure it right? Should :8100 be redirected to 192.168.0.113:81 in this case?
This only guarantees your WANip:8100 will map to 192.168.0.113:81, and doesn't address whether or not dns resolution is correct. I would also be weary of using port numbers on wikipedia's known ports list, as some ISPs will filter those upstream. The last thing is that your router may not want to hairpin that traffic, so if you're not coming in from the outside it might not be a valid test.
Thanks for the pieces of advice! Yes, I tried to connect from external (mobile) network as well.