There are several different components that must work together to achieve what you want. I'll touch briefly upon them, but this answer can never be a comprehensive guide to everything included - that would be several hundreds of pages.
Components
I can identify 3 main components that you need to read up on and configure:
- Docker / Web services (mainly for the port)
- Reverse proxy
- DNS (Domain Name Service)
Docker / Web services
First, understand that each web service (include those run in containers) can be configured to run on different ports. This is especially easy with Docker, since you can expose (publish) and map ports as you like (Docker Reference).
For instance, if you want to remap port 80 in a container to port 8080 on your host machine, you add the -p parameter to start your container:
docker run -p 8080:80 <image>:<tag>
The port before the : colon is the exposed port on the host (can be changed to your liking), and the port after : is the internal port (can not be changed).
Reverse Proxy
Next, the concept of reverse proxy. Simply put, a reverse proxy can take different DNS requests and forward to different hosts and/or ports, as illustrated in the example below (your host is IP 10.10.10.X in this example):
| Website address |
Target host and port |
| sub1.yourdomain.com |
10.10.10.10:8080 |
| sub2.yourdomain.com |
10.10.10.10:9090 |
| sub3.yourdomain.com |
10.10.10.50:10000 |
This is a very simple example. The trick is then of course to have your reverse proxy server running on the normal HTTP and HTTPS ports (80 and 443). Now, when you enter https://sub1.yourdomain.com in a browser, it will redirect traffic on port 443 to 10.10.10.10:8080 as indicated in the table.
Besides, reverse proxying can do a lot of other things, like unifying certificates etc. There are several reverse proxy solutions, like Apache, Nginx, Traefik, HAProxy etc.
DNS (Domain Name Service)
Finally, for the reverse proxy to respond on the DNS subdomains, a DNS resolver must be set up.
If things need to be reachable on the internet, you should configure all the required domain names on a public DNS service (like Cloudflare etc.). Point all domains to your WAN IP address, and have the ports forwarded in your firewall to your reverse proxy server.
In addition, you can also run your own internal DNS service, to expose services on your LAN. Here some common options are Bind9, Unbound etc.
Live example
Just to give you an idea about how some of my web services are set up:
Other relevant Q&As
In addition, there are a couple of other answers here that touch upon this subject:
