Server-Exclusive Maps: Binding a GMod Map to One Server

A Server-Exclusive map is bound to one specific Garry's Mod server: the map file on its own is incomplete, and only a server with a valid license loads the missing parts. Anyone who copies just the BSP therefore does not get a fully working map. The principle makes sharing unattractive and visible, but it is not absolute copy protection.

The underlying problem: every player has the map

For someone to play on your server, their client needs the map file. It is downloaded through FastDL or the Steam Workshop, as described in GMod server maps: FastDL and Workshop. After that the BSP sits on their computer and can be copied.

For a community that has put a lot of time or money into its own map, that is a problem. The map is a unique selling point, and a copy on another server takes exactly that away. A fingerprint can help to match such a copy to a license but does not stop it from running. This is where binding the map to a server comes in.

How binding to a server works

The idea is to split the map into a public part and a private part.

1. During protection, key entities are taken out of the map file, such as spawns, lights and logic.
2. Those entities move into a private server package. It lives only on the server and is not delivered to players.
3. When the map starts, the server asks a license service whether its license is valid.
4. If it is, the server loads the removed entities back in. The map is complete.
5. If it is not, the map stays incomplete.

This works because a GMod server can create entities at runtime through scripts, and server-side scripts do not leave the server. The loaded entities then exist on the server like all others: logic and spawns work there, and whatever players need to see reaches them through the game's normal synchronisation. On a correctly set up server they notice no difference in the game.

In addition, individual doors, triggers or other entities can be listed by their name from Hammer. They stay locked without a valid license.

The last row is crucial. As soon as the original file is public anywhere, the binding has no effect.

Who benefits from a Server-Exclusive map

• Communities with their own exclusive map. If you commissioned a map or bought it exclusively, you do not want to find it on other servers. Custom map vs Workshop map covers the trade-off between an own map and a public one.
• Mappers who license per server. Instead of selling a file that runs anywhere, you sell use on exactly one server.
• Maps with a long lifetime. The longer a server lives off a map, the more the extra effort pays off.

The principle makes less sense for maps that are meant to spread freely and for servers that do not allow outgoing connections.

Requirements and operation

A map bound to a server brings some operational effort:

• You need file access to the server, via FTP or the host's panel.
• The server must be allowed to make outgoing HTTPS connections to the license service.
• The server's system clock should be correct, otherwise the check can fail.
• If the license is bound to an IP address, the binding has to be adjusted after a move to a new address.
• After installation, test the map completely once before it goes live.

A common worry is an outage of the license service. Good implementations therefore use an offline buffer: after a valid check the map keeps running for a limited time, even if the service is briefly unreachable.

Limits

• Full control of a licensed server. Anyone with full control of a licensed server can manipulate scripts and get around the protection. That is true for every solution of this kind.
• Geometry and textures stay in the BSP. The look of the map can still be analysed. That is why obfuscation belongs with it.
• Missing entities can be rebuilt. That takes work and knowledge, but it is not impossible.
• Dependence on a service. Without a first successful check the map does not start in full.

Server-Exclusive is therefore an additional layer. Protect your GMod map from leaks shows how it works together with the others.

Server-Exclusive on bspmarket.de

In BSP Protection, Server-Exclusive is a protection level of its own that includes Fingerprint and Obfuscation. As a result you get the protected map and a private server package as a ZIP. Only entities that can be restored safely are taken out, and the result report shows whether any were found. A map without such entities and without listed names runs in full without a license as well. Only entities that can be restored safely are taken out, and the result report shows whether any were found. A map without such entities and without listed names runs in full without a license as well. bspmarket.de itself describes the mode like this: the map only runs in full on the server with a valid license, and a copy that gets passed on stays incomplete.

Further publicly documented points:

• The license can be bound to the server's IP address.
• A configurable offline buffer bridges short outages. If bspmarket.de reports the license as revoked or expired, the buffer ends immediately.
• If someone uses the server package on another server, the license holder is warned.
• Only the protected BSP from the package belongs in the Workshop.
• There is no promise against manipulated servers.

In the marketplace, Creators can also offer a map as a license for exactly one server, as a one-time purchase or as a rental. With the true exclusivity option, the map is no longer sold after the first license sale. Anyone who bought it before keeps their access, so this does not mean it runs on your server alone. Anyone who bought it before keeps their access, so this does not mean it runs on your server alone. Whether a map is offered this way is shown on its product page. The cost of a protection run of your own is listed under BSP Credits.

FAQ

Can I upload a Server-Exclusive map to the Workshop?

Yes, but only the protected BSP. License file, scripts and entity data stay private on the server, and the unprotected original file is never published.

What happens if the license service is unreachable?

After a valid check the map keeps running on the offline buffer until it expires. On the very first start the server needs a connection.

What happens when I move servers?

If the IP address changes, the license binding has to be adjusted. On bspmarket.de the binding is checked server-side, so the package stays the same. For a license bought in the marketplace, you request the server change in your library.

Does this make my map uncopyable?

No. The BSP can still be copied, but without the server package and a valid license it is incomplete. Anyone with full control of a licensed server can get around the protection.