To make a server for the original PC/Steam Assetto Corsa, install the dedicated server files, match the server’s cars and track to every player’s installation, configure a Content Manager preset or the server_cfg.ini and entry_list.ini files, then forward the configured ports to the host computer. The usual home-hosted defaults are TCP 9600 and UDP 9600 for game traffic plus TCP 8081 for HTTP and lobby traffic, although your own configuration is the authority.
Content Manager is the quickest route for a first server. A packed dedicated folder is easier to move between machines, while AssettoServer adds optional AI traffic, dynamic WeatherFX, Steam authentication and Linux support. The instructions below apply to the original Assetto Corsa (often called AC1), not Assetto Corsa Competizione or Assetto Corsa EVO.
What do you need before making an Assetto Corsa server?
Start by deciding where the server will run and which features you actually need. A small private race for friends can use the stock Kunos acServer.exe on a Windows PC. Freeroam traffic, dynamic weather, plugins, Steam authentication or a Linux machine point toward AssettoServer instead.
Required software and hardware
- The original PC/Steam release of Assetto Corsa. The server systems for Competizione and EVO are different.
- A current dedicated-server package and a text editor for manual configuration.
- The exact cars, tracks, layouts, mods and dependencies that the server will use.
- A host computer that can remain online, with a stable local IPv4 address.
- Router access for port forwarding and permission to change the host’s firewall rules.
The full version of Content Manager makes setup more convenient, but hosting and manual editing are possible without it. If you intend to use AssettoServer’s AI, obtain a compatible fast_lane.ai or fast_lane.aip for the map and place it in that map’s ai/ directory.
Which Assetto Corsa server implementation should you use?
Use Kunos’ server for the fewest moving parts and the most conventional behavior. Choose AssettoServer when its added features or Linux packages justify additional configuration and client prerequisites.
| Consideration | Kunos acServer.exe |
AssettoServer |
|---|---|---|
| Compatibility | Closest to the original game’s standard server behavior. | Replaces the executable, so some original features can behave differently. |
| Operating systems | Typical Windows dedicated-server workflow. | Packages are available for Windows and Linux. |
| Advanced features | Basic race-server functions. | AI traffic, dynamic WeatherFX, plugins and Steam authentication. |
| Client requirements | Standard game content and normal multiplayer setup. | Some features require particular Custom Shaders Patch (CSP) and Content Manager versions. |
AssettoServer’s documentation describes creating the initial configuration with Content Manager as the easiest starting point. You can then run that configuration with the replacement server executable.
How do you install the server and content?
- Install the game and server package. Confirm that the host uses the original PC/Steam game, then download the current Kunos server package or the AssettoServer package for the host operating system.
- Install the content. Put every selected car, track, layout, mod and required dependency on the server. A client must have the same content to pass the multiplayer checksum.
- Create a working folder. Keep the server in its own directory rather than mixing it with the main game installation. AssettoServer specifically warns not to extract its files into the Assetto Corsa folder because its Steam SDK can conflict with the game’s copy.
- Preserve a rollback copy. If you replace
acServer.exewith AssettoServer, rename or copy the original executable first. Restoring it lets you return to the stock implementation when diagnosing a problem.
Folder identifiers matter later. A car’s MODEL and a track’s identifier are normally their directory names, not necessarily the friendly names displayed in a menu. Check the actual folders before entering values in a configuration file.
How do you create a server in Content Manager?
Content Manager gives you a form-based way to generate the same core configuration files. It is the fastest beginner workflow and also a useful way to produce a baseline that you can refine manually.
- Open the Server area. In Content Manager, open the server setup page and create a new preset.
- Name and protect it. Enter the server name players should see and set an administrator password. Use a password that is not reused for another service.
- Select the track and layout. Pick the circuit and layout folder you installed. Check the layout’s pit count before setting capacity.
- Build the entry list. Add each car model and skin that should be available. Keep the number of slots at or below the layout’s available pits; exceeding that limit can cause join crashes or prevent the server from starting correctly.
- Choose the session format. Configure practice, qualifying, race and any timing or session lengths. Pickup mode is generally simpler for a public or friends-only server; booking is the older sign-up workflow.
- Set rules and driving aids. Choose damage, tyre and fuel rates, assists, penalties and other race rules. Make deliberate choices rather than relying on a setting copied from a different preset.
- Set weather and time. Select the weather slots and session time. WeatherFX options are separate from the basic server weather controls when AssettoServer is involved.
- Configure visibility and ports. Enable lobby registration if you want the server to request a public-list entry, and verify the port values shown by the preset.
- Save the preset. Run it inside Content Manager first. Once the stock baseline works, you can pack it for a standalone folder.
Content Manager does not expose every original server setting identically. If a value appears to be ignored, inspect the generated INI files and, for AssettoServer features, extra_cfg.yml directly.
How do you run a portable dedicated server folder?
Running the preset inside Content Manager is convenient on the setup machine. Packing it creates a self-contained folder that is easier to copy to a second Windows computer or deploy alongside a Linux package.
- Use Content Manager’s Pack function to export the server preset.
- Create a new, empty server directory separate from the game’s installation.
- Extract the dedicated-server package into that directory.
- Extract the packed preset into the same directory, preserving its folder structure.
- Confirm that the executable and configuration files are in the locations expected by the package.
- Start the server from that folder and keep its logs there so later troubleshooting has one clear record.
Do not extract AssettoServer into the main Assetto Corsa directory. Its Steam SDK and the game’s own files can conflict when they share that location.
What do server_cfg.ini and entry_list.ini control?
server_cfg.ini defines the race and network behavior; entry_list.ini defines the individual car slots. Together they contain the settings generated by Content Manager and the values you can edit by hand.
server_cfg.ini
This file contains the server name, track and layout, session sequence, rules, weather, lobby registration and network ports. The exact key names depend on the server implementation, so start from the package’s generated file rather than inventing a new schema.
entry_list.ini
Each slot is a block containing a car model and skin, with optional driver name or GUID, ballast and restrictor. AssettoServer can also read an AI behavior value in a slot.
[CAR_0]
MODEL=your_car_folder
SKIN=your_skin_folder
DRIVERNAME=Driver
AI=none
[CAR_1]
MODEL=another_car_folder
SKIN=another_skin_folder
AI=autoThe names in this example are structural values, not universal car names. Replace them with the exact folder identifiers installed on both server and clients. A typo in a model, skin or track folder is enough to produce a startup or join failure.
Which ports does an Assetto Corsa server need?
A common home setup forwards TCP 9600 and UDP 9600 for game traffic and TCP 8081 for HTTP or lobby traffic. Those are defaults, not immutable requirements: the ports written in your server configuration determine what the router and firewall must allow.
| Traffic | Typical default | What to do |
|---|---|---|
| Game TCP | TCP 9600 | Forward to the host PC’s stable local IPv4 address. |
| Game UDP | UDP 9600 | Forward the same configured value; UDP is essential for session traffic. |
| HTTP/lobby | TCP 8081 | Forward when the configuration uses this HTTP port for lobby or server information. |
- Give the host computer a DHCP reservation or another stable local IPv4 address.
- Open the router’s port-forwarding page and create rules for every configured TCP and UDP value.
- Point each rule at the host’s local address, not at a different gaming PC.
- Allow the server executable through Windows Firewall when Windows displays its network prompt. If you denied it previously, add an inbound rule for the executable and the configured ports.
- Set
REGISTER_TO_LOBBY=1when you want the server to request registration in the public lobby.
A server that appears in a local browser is not proof that an internet player can join. Test from a genuinely external connection, such as a friend on another network or a phone hotspot, rather than from another device on the same LAN.
How do you launch and test the server safely?
Use a clean stock baseline before adding community content or plugins. This isolates network and configuration errors from mod errors.
- Start the executable directly or launch the saved Content Manager preset.
- Accept the firewall prompt for the correct network profile.
- Read the startup log for configuration, port-binding and missing-folder errors.
- Test one stock car on one stock track with a small entry list.
- Join from the host and then from another machine. For an internet test, use a connection outside the host’s LAN.
- Add one mod, weather feature or plugin at a time, restarting and testing after each change.
If the stock test works but a later addition fails, remove the last addition first. That controlled sequence is faster than changing ports, cars and weather simultaneously.
How do you add AI traffic with AssettoServer?
AI requires both a compatible spline file and explicit server settings. It is an AssettoServer feature, not a requirement for a basic Kunos server.
- Obtain a
fast_lane.aiorfast_lane.aipcompatible with the selected map. - Place the file in that map’s
ai/folder. - Open AssettoServer’s
extra_cfg.ymland setEnableAi: true. - Assign an AI mode to the relevant car slots in
entry_list.ini:AI=autolets the server choose,AI=fixeduses a fixed AI assignment, andAI=noneleaves the slot for a human. - Restart and inspect the log if AI cars do not appear.
AI behavior depends on the map’s spline. A file for a different layout may load incorrectly or produce no usable traffic, so match the spline to the exact map and layout.
How do you enable dynamic weather and Steam authentication?
Dynamic WeatherFX
Set EnableWeatherFx: true in extra_cfg.yml for AssettoServer’s WeatherFX integration. Dynamic weather requires Custom Shaders Patch (CSP) 0.1.76 or newer on the client, and the selected weather and content must support the feature. A driver without the required CSP features may not see rain or weather transitions even when the server is configured correctly.
Steam authentication
AssettoServer’s Steam-authentication workflow has stricter client prerequisites: CSP 0.1.75 or newer and Content Manager 0.8.2297.38573 or newer. Confirm those versions with every participant before enabling authentication, otherwise a player can be rejected despite having the correct car and track.
Why can nobody join my Assetto Corsa server?
Most failed joins fall into one of four categories: unreachable ports, mismatched content, an oversized grid or an optional feature that a client cannot support.
The server is visible locally but unreachable from the internet
- Compare every port in
server_cfg.iniwith the router’s forwarding rules; do not assume the defaults are still active. - Verify that the forwarding target is the host’s current local IP address.
- Check Windows Firewall and any third-party security suite.
- Test from outside the LAN. Local discovery can work even when internet NAT or firewall rules are wrong.
Checksum or missing-content errors appear
Install identical versions of the car, track, layout, mod and every dependency on the server and each client. Updating a mod on only one side can create a checksum mismatch even when the folder name has not changed.
The server crashes when a player joins
Reduce the entry list so it does not exceed the track layout’s pit capacity. Then verify every MODEL, SKIN and track identifier against the actual folder names.
AI cars do not appear
Check that the map contains the intended ai/fast_lane.ai or fast_lane.aip, that EnableAi is true, and that each slot has the intended AI value. A spline for another layout will not reliably produce traffic.
Rain or weather transitions are invisible
Confirm the client’s CSP version, the AssettoServer WeatherFX setting and compatibility of the selected weather and track. A server-side setting cannot add visual features that a client’s CSP does not support.
Content Manager appears to ignore a setting
Open the generated INI files and AssettoServer’s extra_cfg.yml and edit the relevant value directly. The original server settings are not all represented identically in Content Manager.
Should you host at home or use managed hosting?
Home hosting costs no separate provider fee and gives you direct control, but you must maintain the router, firewall, stable address and uptime. Managed hosting moves the server to a provider’s data center, removes home-router forwarding and usually supplies a panel for editing settings, restarting the process and obtaining support.
| Factor | Home host | Managed host |
|---|---|---|
| Network setup | You configure NAT, firewall and local addressing. | The provider supplies the public network path. |
| Control | Full access to files, executable and operating system. | Access depends on the panel and plan. |
| Cost | No separate game-server bill, but you provide the hardware and connection. | Recurring plan cost; verify current limits and terms. |
| Maintenance | You handle updates, backups and restarts. | The provider may offer automation and support, but policies vary. |
Before choosing a provider, check its current region locations, player limits, backup policy, restart controls and cancellation terms. A hosted panel still uses the same concepts: track and car identifiers, entry-list capacity, sessions, rules and configured ports.
How should you maintain an Assetto Corsa server?
- Keep a copy of the working preset and configuration files before changing content.
- Record the exact versions of cars, tracks, CSP and plugins used by the group.
- Update one component at a time and run the stock-content test after major changes.
- Watch logs after every restart, especially after editing YAML indentation or INI section names.
- Recheck the host’s local IP after router changes or a reboot if outside players suddenly cannot connect.
- Remove unused entry-list slots and obsolete mod references so a stale folder cannot block a join.
Frequently Asked Questions
Can I run an Assetto Corsa server on the same PC I use to drive?
Yes, provided the computer and internet connection can handle both processes. Keep the server in a separate folder and avoid changing its files while a race is running; a second machine is preferable when you need uninterrupted uptime or a large grid.
Do players need Content Manager to join a normal server?
No. A stock Kunos server can be joined with the standard game client when the required content matches. Content Manager becomes necessary only for workflows or features that specifically depend on it, such as some AssettoServer authentication and WeatherFX setups.
How can I hide a private server from the public lobby?
Disable lobby registration in the server configuration instead of setting REGISTER_TO_LOBBY=1. Friends can then connect using the server’s direct address and configured game port, subject to your router and firewall rules.
What happens if a track has fewer pits than the number of players I want?
The layout’s pit capacity is the hard limit for the entry list. Choose a different layout or track with more pits; adding extra slots in the INI does not create usable starting positions and can lead to join or startup failures.