Every American Truck Simulator dedicated server is controlled by a single file: server_config.sii. It covers everything from your session name and password to player limits, ports, and moderator permissions — and most of it is shared with Euro Truck Simulator 2's dedicated server, just with different defaults.
This reference walks through every setting you'll find in the file, grouped by what they control, along with their default values and what each one actually does.
You'll find server_config.sii at .local/share/American Truck Simulator/ inside your server's files. For a full walkthrough of navigating there, see our guide on adding moderators — this article focuses purely on what each setting means.
Session Info
These settings control what players see before and after connecting.
Player & Vehicle Limits
max_vehicles_total caps the combined number of player and AI vehicles active in the session at once. max_ai_vehicles_player and max_ai_vehicles_player_spawn control how much AI traffic gets generated around each individual player.
Networking & Ports
connection_virtual_port and query_virtual_port route through Steam's relay network and must each be a value between 100 and 200 — they don't need port forwarding.
connection_dedicated_port and query_dedicated_port are physical ports used to list your server in Steam's session browser. If you're hosting on a LAN, query_dedicated_port must fall between 27015 and 27020. Unlike the virtual ports, both of these need TCP and UDP forwarding rules on your router — MintServers handles this automatically for hosted servers.
server_logon_token at steamcommunity.com/dev/managegameservers using American Truck Simulator's game App ID (270880) — not the dedicated server's App ID.
Gameplay Flags
⚙️ What Each Flag Does
player_damage:Whether players can damage each other's vehicles and cargo. Set to false for a purely cosmetic, no-collision-damage convoy.traffic:Whether AI traffic vehicles appear on the roads at all.hide_in_company:Whether other players' vehicles are hidden from view while they're inside a company or garage area.hide_colliding:Whether a vehicle is temporarily hidden right after a teleport, such as fast travel, if it would otherwise be colliding with something.force_speed_limiter:Forces every truck's speed limiter on, regardless of each player's own in-game setting.mods_optioning:Determines whether mods that their creators have flagged as "optional" are actually treated that way. With the default of false, those mods are still enforced like any other; set it to true to let players connect without needing them installed.timezones:Controls how in-game time zones behave across the map, accepting a value from 0 to 2. SCS's own documentation doesn't detail exactly what each value changes, so it's worth testing on a private session first if precise time-zone behavior matters to you.service_no_collision:Disables collisions between vehicles while parked in service areas like truck stops and repair shops.in_menu_ghosting:Disables collisions with other players' vehicles while your own game menu is open and the game is paused.name_tags:Shows each player's name above their truck.
Settings Dedicated Servers Ignore
Two fields are carried over from the config format used by regular player-hosted sessions but have no effect on a dedicated server, according to SCS's own documentation: friends_only and show_server. Both are safe to leave at their defaults — changing them won't do anything here.
Moderators
moderator_list controls who gets admin permissions on your server. The default is moderator_list: 0, meaning no moderators, and you list Steam64 IDs below it to add them.
We cover this in full, including exactly how to format the list and what admin commands moderators get, in our guide on how to add moderators to your American Truck Simulator server.
That covers every setting in server_config.sii. Most changes take effect the next time your server starts, so remember to stop and restart it in your MintServers panel after editing. If anything behaves differently than expected, open a support ticket and we will help you track it down.