Disclosure: I'm Antonin Courtadon, founder of ACLClouds.
Nobody wants to share 203.0.113.45:25565 with friends. A name such as play.example.com is easier to remember, easier to change when the server moves, and easier to put on a poster. That is what a subdomain does: it attaches a readable name to a service.
This article explains how that mapping works, where it stops working, and how to get a free subdomain on aclclouds.online for a game server, a bot dashboard or a small website.
How a subdomain works
The Domain Name System (DNS) translates names into addresses. A domain such as example.com has records; a record of type A points a name to an IPv4 address. A CNAME points a name to another name. A subdomain is just a name below the domain, such as play.example.com, with its own record.
When someone types play.example.com, their computer asks DNS for the address, receives the IP of your server, and connects to it. The rest is up to the service listening on that address.
Two things DNS does not do:
- It does not choose the port. The name leads to an IP. The port (for example 80 for HTTP, 443 for HTTPS, 25565 for Minecraft) is still set by the service and by the client.
- It does not guarantee the server is running. A correct name pointing to a stopped server gives the same error as a wrong IP.
Web apps versus game servers
For a website or a dashboard, the subdomain is usually enough: the browser uses port 443, and a reverse proxy routes the request to your app. You set the record and the proxy handles the rest.
For a game server, the situation depends on the game:
- Some games let the client connect to a hostname and port typed by the player (
play.example.com:25565). The subdomain works, but the port must still be open and reachable. - Minecraft also supports an SRV record (
_minecraft._tcp), which tells clients the port to use. If the name isplay.example.comand the SRV record points to the port, players can type just the name. Check your server software's documentation before relying on it, because support varies. - Some games and bots need a fixed IP. A subdomain can change without disturbing players, but the server's address still has to be stable.
Be careful with the word "free". A free subdomain makes a name available. It does not make a game server free to run, and it does not open ports for you.
What ACLClouds offers
ACLClouds provides free subdomains on aclclouds.online. The free-subdomains page is in the client dashboard. Check on that page which kinds of service a subdomain can be attached to before you plan your setup, because the rules can differ between hosted services and external machines.
Practical notes:
- Free subdomains are on aclclouds.online. If you want your own domain (for example
play.yourbrand.com), you set up that domain's DNS records yourself, at your registrar. - A subdomain is a name, not a hosting slot. You still need a service running behind it.
- Keep the record pointing at the right address. When you move a server, update the record and wait for it to propagate. Old caches can keep the previous address for a while.
Step by step: a free subdomain for a small web app
Imagine a small web dashboard for a project, listening on port 3000.
- Open the free subdomains page in the ACLClouds dashboard and reserve a name, for example
mybot. The address becomesmybot.aclclouds.online. - Attach the name to the service it should reach, using the fields the page shows. The exact screens can change, so follow the labels on the page rather than a remembered layout.
- Make sure your app listens on the port it is attached to, and that it binds to all interfaces (
0.0.0.0), not only to127.0.0.1. An app bound to localhost is invisible from outside. - Open
https://mybot.aclclouds.onlinein a browser. If it does not load, check the app logs first, then the attachment, then the port.
For a game server, the first steps are the same. The difference is that a game client connects with a hostname and port, so you must also make sure the game's port is reachable through the firewall rules of your server.
Comparison: what to check on a subdomain service
| What to check | Why it matters | ACLClouds free subdomains |
|---|---|---|
| Domain used | Determines how people reach you | aclclouds.online |
| Cost | Free names still need a running service | Free to reserve |
| Your own domain | Brand and long-term control | Set up in your own DNS |
| Record management | Lets you change the target | Managed from the dashboard |
| Game ports | DNS does not open them | Check your service's port and firewall |
| Changes | Old caches delay the switch | Plan a few minutes of propagation |
Limits, stated plainly
- A subdomain does not replace security. Do not expose a dashboard or an admin panel without authentication.
- A game port is still a port. If your home network blocks it, the name will not help.
- Free subdomains are for the platform's domain. A brand-new domain with your own name is a separate setup and a separate cost.
- Changes are not instant. Expect minutes, sometimes longer, before every client sees a new target.
Frequently asked questions
Is a free subdomain the same as a domain?
It is a name under a domain that someone else owns. On aclclouds.online, the domain belongs to ACLClouds and the subdomain is yours to use within the platform rules.
Can I use a free subdomain for a game server?
Yes, if the server software supports a hostname and port, and if the port is open. Test with a friend outside your network before you announce the address.
Why does my site show an error after I set the subdomain?
Check that the app runs, that it listens on the right port and interface, and that the record points at the target you chose. Propagation can take a little time after a change.
Do I need an SRV record?
Only for games that support it, such as Minecraft, and only if you want players to type the name without a port. Otherwise type the port after the name.
What happens if I stop the service?
The name still exists, but nothing answers. Visitors see a connection error, not a redirect, so tell your users about maintenance.
Next steps
Reserve a free subdomain, point it at a test service, and check that it loads from a phone on mobile data. That single test catches most setup mistakes. The English documentation is at https://aclclouds.com/en/ and the French one at https://aclclouds.com/fr/.
Antonin Courtadon, founder of ACLClouds · https://aclclouds.com
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