Game server glossary: hosting terms explained in plain English

This glossary defines the terms that come up when you run or rent a game server, in plain language and with what each one means in practice. Dedicated server, tick rate, TPS, query port, RCON, game server login token, SteamCMD, egg, allocation, vCPU, OOM, wipe, whitelist and the rest are grouped by topic rather than alphabetically, because most of them only make sense next to their neighbours. Each entry says what the thing is, why you would care, and where to read more. If a term in a guide or a support reply left you guessing, it is probably here.

Kinds of server#

• Dedicated server - a program that runs the game world without a player attached. It has no graphics, keeps the world running when nobody is online, and accepts connections from players' game clients. Most games ship it as a separate free download. What is a dedicated game server explains it in full.
• Listen server - a game hosted from inside one player's game. The host plays and serves at once; when they quit, the server goes. Fine for an evening, poor for anything persistent.
• Peer-to-peer - no server at all; players' machines exchange state directly or through one elected host. Common in console and co-op games. Cheating and lag are harder to control.
• Headless - running without a display or graphics. Every dedicated server on a host is headless. Unity servers use -batchmode -nographics to get there (Unity dedicated server basics); Factorio calls its server build the "headless" version.
• Instance - one running copy of a server. One machine can run many instances of the same game, each with its own ports and files.
• Cluster - several servers linked so players or items can move between them. ARK and Atlas use the word; Minecraft networks do the same thing with a proxy.
• Proxy (game) - a server that sits in front of several game servers and passes players between them, such as Velocity or BungeeCord for Minecraft. Players connect to one address and move between worlds without reconnecting. Velocity proxy networks cover the Minecraft case.
• Modded and vanilla - a vanilla server runs the game as shipped; a modded one adds mods or plugins. "Semi-vanilla" usually means plugins that leave gameplay largely unchanged.

Hardware and resources#

• vCPU - a virtual CPU core: a share of a physical core's time. Hosts sell CPU as vCPU or as a percentage of one core, so "250%" means two and a half cores' worth. A hard limit means the server is throttled at that share, not given more when the machine is quiet. Shared CPU and noisy neighbours explains how sharing works.
• Single-thread performance - how fast one core is. Most game servers run their simulation on one main thread, so a faster core beats more cores. CPU vs RAM for game servers is the long version.
• RAM - memory. Holds the loaded world, players, entities and mods. Running out is fatal rather than slow - see OOM below.
• Disk and NVMe - storage for the game files, saves, logs and backups. NVMe is a fast type of solid-state storage; it shortens world loading and save freezes. What NVMe actually changes separates the real gains from marketing.
• OOM - out of memory. When a process hits its memory limit, the operating system's OOM killer stops it. On a game server that looks like a sudden crash with no game error. Linux swap and the OOM killer explains it.
• Swap - disk used as overflow memory. Lets a machine survive briefly when RAM is full, at the cost of becoming very slow. Game servers in swap lag so badly that being stopped is often kinder.
• Container - an isolated environment for one server, with its own limits on CPU, memory and disk. Panels such as Pterodactyl run each server in its own Docker container.
• VPS, VDS, dedicated (hardware) - a virtual private server is a virtual machine on shared hardware; a VDS is the same idea with resources reserved for you; a dedicated server is a whole physical machine. Confusingly, "dedicated server" also means the game program above. VPS vs VDS vs dedicated server untangles them.

Networking#

• IP address - the number players connect to, such as 203.0.113.10. IPv4 addresses are scarce, so servers often share one and are told apart by port.
• Port - a number that identifies one service on an address, from 1 to 65535. A game server listens on one or more. 203.0.113.10:27015 means port 27015 at that address. Game server ports explained covers the common ones.
• Allocation - in a hosting panel, an IP and port pair assigned to your server. Extra allocations are extra ports, for query, RCON or a second service.
• UDP and TCP - the two transport protocols. Most games send gameplay over UDP, which tolerates loss; RCON, web panels and Minecraft use TCP. A firewall rule for the wrong one is a classic "server runs but nobody can connect". TCP vs UDP for game servers.
• Query port - the port a server browser talks to, to read the server's name, map and player count. Separate from the game port in many games, the same port in others. Query ports and A2S.
• A2S - Valve's server query protocol, used by Steam's browser and most server-list sites to read server information.
• Master server - the central list a game's browser reads. A server registers with it to appear in the in-game list.
• Ping or latency - the round trip time between a player and the server, in milliseconds. Distance is most of it.
• Jitter - how much latency varies from one packet to the next. High jitter feels worse than steady high ping.
• Packet loss - packets that never arrive. Even 1-2% causes rubber-banding. Latency, jitter and packet loss has all three.
• Port forwarding - telling a home router to send incoming traffic on a port to one machine. Needed to host from home; not needed on a hosted server.
• NAT and CGNAT - network address translation lets many devices share one public address. Carrier-grade NAT does it at the provider, which usually makes hosting from home impossible. NAT and CGNAT for game hosts.
• DDoS - a distributed denial-of-service attack: a flood of traffic meant to knock a server offline. DDoS attacks on game servers explained.
• A record and SRV record - DNS records that point a name at an address, and (for some games, notably Minecraft) at a specific port too. SRV records for Minecraft.

A few default ports come up so often that they are worth recognising on sight:

Performance#

• Tick - one step of the server's simulation, in which it processes input, moves things and sends updates.
• Tick rate - how many ticks a server runs per second. CS2 runs at 64, Minecraft at 20, TF2 at 66. Higher is more responsive and costs more CPU. What tick rate actually means.
• TPS - ticks per second actually achieved. Minecraft players use it to mean server health: 20 TPS is perfect, anything lower means the server cannot keep up. Why TPS drops.
• MSPT - milliseconds per tick: how long each tick takes. At 20 TPS each tick has a 50 ms budget; above that the server falls behind.
• Server FPS - in some games (Rust, ARK, Unity and Unreal titles generally) the simulation rate is expressed as frames per second. Same idea as tick rate.
• Lag - a catch-all for "the game is not responding as it should". It may be network (ping, loss), server (low TPS) or client (low frame rate). Diagnosing it starts with which one.
• Rubber-banding - being pulled back to where you were a moment ago, because the server corrected your position. Usually packet loss or a struggling server.
• Desync - client and server disagree about the state of the world. Doors that are open for you and shut for others, enemies in two places.
• Entity - anything in the world that is not terrain: players, creatures, items on the ground, vehicles, machines. Entity count is the usual reason a mature world runs slower than a new one.
• Chunk and zone - the pieces a world is divided into for loading and simulation. Minecraft uses chunks of 16 by 16 blocks; Valheim uses zones owned by nearby players.
• Profiler - a tool that measures what the server spends its time on, such as spark for Minecraft or resmon for FiveM. The only reliable way to find the cause of lag. spark profiler.
• Memory leak - memory that grows and is never freed, until the server runs out. Game server memory leaks.

Administration and access#

• Console - the server's live text output and command line. Where you read errors and type admin commands. How to read a server console.
• RCON - remote console: a protocol for sending console commands to a server over the network, protected by a password. Powerful and risky. RCON safely.
• Admin and op - a player with elevated rights in-game. "Op" is Minecraft's word, short for operator.
• Permissions - fine-grained rights, such as "may kick" or "may use /fly", given to players or groups by a plugin such as LuckPerms or SourceMod.
• Whitelist (also allowlist) - a list of player accounts allowed to join. Everyone else is refused. Whitelist vs password.
• Ban list - accounts or addresses refused entry. Stored in a file or database, sometimes shared across servers.
• SteamID - the unique number Steam gives every account, used for admin lists, bans and whitelists. Usually written as a 17-digit SteamID64.
• GSLT - game server login token: a token tying a server to a Steam account, required for some games (CS2) and optional for others. Steam game server tokens.
• Anti-cheat - software that detects cheating, either on the client (Easy Anti-Cheat, BattlEye, VAC) or on the server. BattlEye and Easy Anti-Cheat on servers.
• Subuser - a second person given access to the hosting panel for one server, with chosen permissions. Subusers and least privilege.
• 2FA - two-factor authentication: a code from an app on top of the password. Two-factor on your panel account.

Software, mods and content#

• SteamCMD - Valve's command-line Steam client, used to install and update dedicated servers. SteamCMD explained.
• App ID - the number identifying a game or server on Steam. A game's server usually has a different app ID from the game itself.
• Beta branch - an alternative version of a game on Steam, such as a test build or an older version. Selected with -beta in SteamCMD.
• Build and version - a specific release of the game. Clients and servers usually must match exactly.
• Workshop - Steam's mod hosting. Many servers can download Workshop items by ID. Steam Workshop mods on dedicated servers.
• Mod - anything that changes the game. Often needs installing on both server and every client.
• Plugin - a server-side extension, usually needing nothing on clients. Minecraft's Paper plugins, SourceMod plugins and Oxide plugins are examples.
• Framework or loader - the software that lets plugins or mods run at all: BepInEx, Oxide, SourceMod, Fabric, Forge, NeoForge, txAdmin's FiveM stack. It usually has to be updated when the game updates.
• Load order - the order mods load in, which matters when they change the same things. Mod load order explained.
• Datapack - a Minecraft content package of JSON and functions that needs no mod loader. Minecraft datapacks guide.
• FastDL - a web server holding compressed custom content for Source games, so players download maps quickly instead of through the game server.
• Map rotation or map cycle - the list of maps a round-based server plays in order. Game server maps and map rotation.
• Fork - a modified copy of server software. Paper is a fork of Spigot; Purpur is a fork of Paper.

Several of these terms meet in one line. This SteamCMD command installs a server by its app ID and checks every file against the current build on Steam:

$ steamcmd +force_install_dir ./server +login anonymous \    +app_update 896660 validate +quit

896660 is the Valheim dedicated server's app ID, and validate repairs anything that differs from the official build. Adding -beta <branch> after the app ID would install a beta branch instead; the branch names are whatever the developer publishes, and some need a password passed with -betapassword.

Saves and the server's lifecycle#

• Save or world file - where the game stores the world state on disk. Its format and location vary by game. Game server save files explained.
• Autosave interval - how often the server writes the world to disk. Anything since the last save is lost in a crash. Autosave intervals.
• Seed - the number a world generator starts from. Same seed, same terrain.
• Wipe - resetting a server's world, player progress or both. Rust wipes monthly; others wipe rarely or never. "Map wipe" and "blueprint wipe" are Rust's two kinds.
• Rollback - restoring the world to an earlier state, from a backup or a logging plugin.
• Backup and snapshot - a copy of the server's files from a point in time. A backup is only useful if it restores. Backups that actually restore.
• Scheduled task or cron - an action run automatically at set times, such as a nightly restart or backup. Cron expressions explained.
• Crash loop - a server that crashes on start, restarts, and crashes again. Game server crash loops diagnosis.
• Uptime - how long a server has run since its last start, or the share of time a service is available.

Hosting panels#

• Panel - the web interface a host gives you to start, stop and configure a server. Pterodactyl is a widely used open-source one. Pterodactyl panel explained.
• Wings - Pterodactyl's daemon on each machine, which runs the containers and talks to the panel.
• Egg - Pterodactyl's recipe for a game: how to install it, which container image to use, the startup command and its variables. Pterodactyl eggs for game servers.
• Startup variables - the settings an egg exposes on the Startup tab, such as the server name, max players or game version. They fill in the launch command.
• SFTP - secure file transfer, the way to move large files to and from the server. SFTP and the file manager.
• Node - one physical machine in a host's fleet, running many customers' servers.

FAQ#

What is the difference between a dedicated server and a dedicated machine?

A dedicated game server is the program that runs the world without a player attached. A dedicated machine is a whole physical computer rented to one customer. You can run a dedicated game server on shared hardware, and most people do.

Is tick rate the same as TPS?

Nearly. Tick rate is the target number of simulation steps per second; TPS is how many the server actually manages. When a server is healthy they are equal. When it struggles, TPS falls below the tick rate.

What does "unmetered" bandwidth mean?

That you are not billed per gigabyte transferred. It does not mean unlimited capacity: the connection is still shared and still has a speed, and fair-use rules still apply. Bandwidth and fair use explains it.

What is the difference between a mod and a plugin?

Loosely, a plugin runs only on the server and players need nothing extra, while a mod changes the game for everyone and usually needs installing on each client too. Communities use the words inconsistently, so check each item's own instructions.

Why do guides say "query port" and "game port" separately?

Because many games use two ports: one for gameplay and one for answering server browsers. If only the game port is open, people can join by IP but the server never appears in the list.