An Assetto Corsa dedicated server is the program that runs an online session on its own: the track, the cars, the grid and the race rules, open to your friends or the whole lobby 24/7. It ships with the game. You configure it with Kunos’s Server Manager or Content Manager, it reads two files (server_cfg.ini and entry_list.ini), and players connect on port 9600 (TCP and UDP) plus 8081 for the lobby. This guide shows how to host an Assetto Corsa server step by step, what it needs, how traffic and drift servers are built, and how to fix the connection errors everyone runs into.
What an Assetto Corsa dedicated server is (and isn’t)
Online racing in Assetto Corsa runs on a dedicated server, either one somebody else runs or your own. Running your own gives you a private server with your track, your cars, your session lengths and your password. The server is small, about 2–4 GB of RAM, and it runs on Windows or Linux.
If you were searching for a specific community server like No Hesi, Pushin P, TGA, Velocity, High Force or Swim, those are servers you join from the lobby or through their Discord, not software you install. What you can do is build your own server in the same style: a highway cruise with AI traffic, a drift or touge night, a track day on the Nordschleife or a car meet. All of that starts with the same dedicated server.
This guide covers the original Assetto Corsa. Assetto Corsa Competizione and Assetto Corsa EVO are separate games with separate servers; there’s a short note on ACC further down.
Assetto Corsa server requirements
- RAM: 2–4 GB. Race sessions are light on memory, even with a full grid.
- CPU: steady single-core speed matters more than core count. The server keeps every car’s position in sync many times a second, and an overloaded CPU shows up as warping cars.
- OS: Windows (
acServer.exe) or Linux (acServer, the Linux build in the same server package). - Content: every car and track the server uses must be in its
contentfolder, and every player needs the same content installed. - Network: a stable upload and ports you can forward (see ports). Each player in the session costs upload bandwidth.
How to host an Assetto Corsa server: three ways
Every Assetto Corsa multiplayer server setup ends in the same place: a running acServer with a config folder and the content it needs. The three routes differ in how you get there.
Option A: Content Manager (the easiest way to make a server)
Most players already use Content Manager as their launcher, and it has a server section built in. To create a server in Content Manager:
- Open Content Manager and go to the Server section. Create a new preset.
- Pick the track (and layout), add the cars, set a server name and password, and fill in the sessions (practice, qualify, race) and assists.
- On the entry list, add a slot for every car you want on the grid.
- Start it from Content Manager to host it from this PC, or click Pack to export a ready-to-upload folder (config plus the content it needs) for a remote or hosted dedicated server.
Content Manager also understands servers that offer downloads of missing cars, skins and tracks, which saves a lot of “server contains unavailable content” messages for modded servers.
Option B: Kunos’s Server Manager (comes with the game)
- Open the game folder (Steam > Assetto Corsa > Manage > Browse local files) and go into
server, where the server manager andacServer.exelive. Open the server manager. - Set the name, track, cars, sessions and entry list in its tabs, then save.
- Either run
acServer.exefrom the same folder to host from this PC, or use the manager’s packaging option to build a server folder (with the content it needs) to copy to another machine.
Option C: a Linux dedicated server
The Linux binary acServer comes in the same package. You can copy the server folder from a Windows install (with its content), or download the Assetto Corsa Dedicated Server app (Steam app 302550) with SteamCMD. Unlike most server tools, that download needs a Steam login, not an anonymous one. Then:
cd ~/acserver
chmod +x acServer
./acServerLinuxGSM supports it as acserver if you want start, stop, update and monitoring commands for free. For a web GUI, community server managers such as the open-source ACServerManager edit the same two files from your browser and start and stop the server for you.
Assetto Corsa server configuration: server_cfg.ini
Whatever tool you use, the result is cfg/server_cfg.ini. The lines that matter most:
[SERVER]
NAME=Friday Night Touge
CARS=bmw_m3_e30;ks_toyota_ae86
TRACK=magione
CONFIG_TRACK=
PASSWORD=friends-only
ADMIN_PASSWORD=something-long-and-private
MAX_CLIENTS=18
UDP_PORT=9600
TCP_PORT=9600
HTTP_PORT=8081
REGISTER_TO_LOBBY=1
PICKUP_MODE_ENABLED=1
LOOP_MODE=1
[PRACTICE]
NAME=Practice
TIME=10
IS_OPEN=1
[RACE]
NAME=Race
LAPS=5
WAIT_TIME=60
IS_OPEN=1| Setting | What it does |
|---|---|
CARS |
Car folder names allowed on the server, separated by semicolons |
TRACK / CONFIG_TRACK |
Track folder name and layout (empty = default layout) |
MAX_CLIENTS |
Player limit. Can’t be higher than the number of slots in the entry list |
REGISTER_TO_LOBBY |
1 shows the server in the online server list, 0 keeps it private or LAN-only |
PICKUP_MODE_ENABLED |
Players take any free slot with the car they pick, instead of a booked grid |
LOOP_MODE |
Restart the session list after the race, so the server runs forever |
SUN_ANGLE |
Time of day, from -80 to 80 (16 is about 2 pm) |
[WEATHER_0]… |
Weather presets, such as clear or heavy clouds |
ABS_ALLOWED, TC_ALLOWED, STABILITY_ALLOWED |
Which assists drivers may use |
DAMAGE_MULTIPLIER, FUEL_RATE, TYRE_WEAR_RATE |
Percent of normal; 100 is realistic |
The stock server’s weather presets set the sky and temperatures. Dynamic weather, rain included, comes from Custom Shaders Patch’s WeatherFX on the clients, which a custom server such as AssettoServer can drive.
entry_list.ini: the grid
The entry list defines every car slot, so the size of your grid is set here, not by a slot count. One block per car, numbered from CAR_0:
[CAR_0]
MODEL=bmw_m3_e30
SKIN=
SPECTATOR_MODE=0
DRIVERNAME=
TEAM=
GUID=
BALLAST=0
RESTRICTOR=0
[CAR_1]
MODEL=ks_toyota_ae86
SKIN=
...Leave GUID empty for an open slot, or put a player’s Steam ID in it to reserve the slot for them. BALLAST (kg) and RESTRICTOR (percent) are how leagues balance high hp cars against slower ones. Every MODEL must exist in the server’s content/cars folder and be listed in CARS. A grid of around 24 is what most servers run in practice.
Assetto Corsa server port forwarding
| Port | Protocol | Used for |
|---|---|---|
| 9600 | UDP | Game traffic (UDP_PORT) |
| 9600 | TCP | Game traffic (TCP_PORT, must match the UDP port) |
| 8081 | TCP | HTTP: lobby registration |
Forward all three on your router to the PC running the server and allow them through the firewall. If you change them in server_cfg.ini, forward the new numbers instead. The server can even fail to start when it can’t reach the Kunos master server, so open the ports before you troubleshoot anything else.
Without port forwarding: LAN and Hamachi
For a LAN server, everyone on the same network can join with REGISTER_TO_LOBBY=0 and no forwarding at all. Friends elsewhere can join a LAN-style server through a virtual LAN tool such as Hamachi, which puts everyone on one private network. It works, but it adds latency and it’s fiddly to keep running. The other way to make an Assetto Corsa server without port forwarding is to put it on a hosted server, such as Assetto Corsa server hosting.
Admin commands
Set ADMIN_PASSWORD, join, open the chat and type /admin yourpassword. Admin rights last for that session. Useful commands on the stock server:
| Command | What it does |
|---|---|
/next_session |
Skip to the next session (practice to qualify, and so on) |
/restart_session |
Restart the current session |
/kick <name or car id> |
Kick a player |
/ban <name or car id> |
Ban a player |
/client_list |
Show players and their car slot numbers |
/ballast <car id> <kg> |
Add ballast on the fly |
Commands differ slightly between server versions and custom servers; AssettoServer, for example, uses /kick_id and /ban_id and adds /settime and /setweather.
Mods: adding cars and tracks to the server
Car and track mods go into the server’s content/cars and content/tracks folders, and must also be installed on every player’s game, which is why most modded servers publish a content pack or a download link next to the server address. When a client is missing a car or track, the join simply fails, often without naming the missing item. Content Manager’s server wrapper can offer missing cars, skins and tracks for download straight from the server, which solves most of this for a modded server.
Traffic servers, drift servers and free roam
The stock server is built for races: sessions, laps and a grid. Free roam servers with AI traffic, the kind people mean by “assetto corsa traffic server”, “highway server”, “cut up server” or a GTA-style city map with traffic, run on a custom server instead, usually AssettoServer.
- It replaces
acServerand reads the sameserver_cfg.iniandentry_list.ini, plus its ownextra_cfg.yml. Windows and Linux builds are on its GitHub releases page. Don’t extract it into your Assetto Corsa folder. - How to add traffic: put
fast_lane.ai(or.aip) in the track’sai/folder, setEnableAi: trueinextra_cfg.yml, and give the traffic slotsAI=autoorAI=fixedinentry_list.ini. Its AI defaults are tuned for Shutoko Revival Project, a community map of Tokyo’s (Japan’s) high speed Shuto Expressway, so other maps may need tuning. - It’s built for free roam: race and qualifying sessions with lap times aren’t supported yet. Keep the stock server for race nights.
- Admins listed in
admins.txtlog in automatically; Steam authentication, dynamic weather (including rain through Custom Shaders Patch) and plugins are switched on inextra_cfg.yml.
Drift and touge servers don’t need AI at all: a drift or touge server is a stock server on a mountain or drift track, pickup mode on, long practice session, damage low. Police chase, cops and robbers and roleplay servers are free roam servers as well.
Assetto Corsa Competizione dedicated server
ACC has its own dedicated server, and it’s configured differently: JSON files in its cfg folder instead of ini files. configuration.json holds the ports and connection limit, settings.json the server name, passwords, car group and rating requirements, event.json the track, sessions and weather, with eventRules.json, assistRules.json and an optional entrylist.json beside them. ACC expects those files saved as UTF-16; save one as UTF-8 and it ignores your changes. It’s the server to look at for league or competition nights in ACC, and a separate setup from the original game covered here.
Common Assetto Corsa server problems and fixes
| Problem | Most likely cause | Fix |
|---|---|---|
| “Can’t connect to remote server” / “Cannot connect” / “Unable to contact server” | Ports not forwarded, server down, or the server’s IP changed | Forward 9600 TCP+UDP and 8081 TCP, check the server window is running, re-add the server |
| “Game crashed: can’t connect to remote server” | Same network problem, reported after the game launched | Same fix; also check the server log shows your connection attempt |
| Crashes when joining a server | Missing or different car or track version on the client | Install the exact content pack the server uses |
| “Server contains unavailable content” | A car or track on the server isn’t installed on your game | Download the missing content (Content Manager can if the server offers it) |
| “No available cars” | All slots of the car you picked are taken or reserved | Pick another car, or add slots to entry_list.ini |
| “You are not whitelisted on this server” | Slots locked to GUIDs, or a whitelist on a custom server | Ask the admin to add your Steam ID |
| “Server auth failed” | Steam authentication on the server, outdated CSP or Content Manager | Update Custom Shaders Patch and Content Manager |
| Server not showing up in the list, or LAN server not showing up | HTTP port blocked, REGISTER_TO_LOBBY=0, or the lobby is unreachable |
Forward 8081, set REGISTER_TO_LOBBY=1; for LAN, join by IP |
| “The server seems to be unavailable” / “did not respond in given time” | Server overloaded, still loading the track, or a connection issue on the route | Give it a minute after start, check CPU use, try again |
| Server crashing on start | A car in CARS or entry_list.ini missing from content, or a typo in a folder name |
Check every MODEL and TRACK name against the content folders |
Skip the setup: rent an Assetto Corsa server
Hosting your own means a PC that stays on, three ports to forward and two ini files that have to agree with each other and with your content folder. With Assetto Corsa server hosting on GameTeam the server stays online between race nights with no port forwarding, and you pay per GB of RAM (a 4 GB server is $1.96 a week on the Budget plan, or $1.99/GB billed monthly) with unlimited slots on our side; your entry list still sets the grid. The built-in AI copilot writes the files for you: tell it “Nordschleife, 20 slots of BMW M3 E30, 15 minutes practice, 8-lap race, damage off” and it builds server_cfg.ini and entry_list.ini and restarts, or ask “why can’t anyone join since I added the new track?” and it reads the server log and tells you which content is missing.
FAQ
Is an Assetto Corsa server free?
The dedicated server comes free with the game. Running it costs a PC that stays on, or a hosting fee.
How do I play Assetto Corsa with friends on a private server?
Set a PASSWORD in server_cfg.ini, start the server, and share the password. Friends find it by name in the online server list (in the game or in Content Manager) and enter the password to join.
How many players can join an Assetto Corsa server?
As many as there are slots in entry_list.ini, up to MAX_CLIENTS. Most race servers run grids of about 24.
Can I add AI to an Assetto Corsa server?
The stock server has no AI drivers. For AI traffic on a free roam server, use AssettoServer with EnableAi and AI slots in the entry list.
What’s the best Assetto Corsa server setup for a small group?
For the best results: a stock server, pickup mode on, one track, a short car list everyone already owns, and a password. Add mods one at a time, and only once everybody has them installed.