Multiplayer

Civilization 4 is played online through Steam (Steamworks replaced GameSpy in June 2014), on a LAN, in Hot Seat on one PC, by e-mail, and on Pitboss servers for long games; the Steamworks update removed Direct IP, which survives only in an unsupported beta branch of the original release, and Steam no longer supports the Mac version's online play.

Civilization 4 can be played with other people in five ways: over the Internet (through Steam since 2014, through GameSpy before that), on a local network (LAN), in Hot Seat on one computer, by e-mail, and on a Pitboss server that keeps a game running for days or weeks. The Civilization IV manual (pp. 172-173) describes the first four, plus a Direct IP connection, and LAN and Internet games can use traditional turns or simultaneous movement. GameSpy's servers closed on May 31, 2014, and on Jun 5, 2014 2K released a Steamworks update that "replaces GameSpy with Steamworks for multiplayer functionality", identical to the old version except that Direct IP was removed. The manual's own advice for newcomers still holds: play a few games against the computer first, because multiplayer "can also be incredibly cutthroat and high-pressure" (p. 10).

3D map of desert and grassland with orange and yellow borders, several elephants carrying towers, horses and carts, and labels for Coventry, Granary; York, Catapult; and Frankfurt. — Gameplay from the Steam store page: war elephants, chariots and catapults with yellow banners cross dry land between the cities of Coventry, York and Frankfurt in 1125 AD. Firaxis Games and 2K

Quick facts

Modes	Internet, LAN, Hot Seat, Play by E-mail, Pitboss
Online service	Steamworks since Jun 5, 2014; GameSpy before
GameSpy closed	May 31, 2014
Direct IP	Removed by the Steamworks update; kept in an unsupported beta branch
Turns	Traditional or simultaneous; optional turn timers
Teams	Locked alliances; simultaneous team turns in Beyond the Sword
Pitboss	Persistent server for long games, from patch 1.61 and Warlords
Mac	Online multiplayer no longer supported (Steam)
Mods online	Every player loads the same mod first (Advanced, Load a Mod)

Source: Civilization IV manual, pp. 22 and 170-173; 2K on Steam, Jun 5, 2014; 2K Support (archived); Steam.

Online play through Steam

Online games of Civilization 4 run on Steamworks, Valve's online service, since 2014. When GameSpy announced it would shut down, 2K listed which of its games would move: 2K Support scheduled its GameSpy titles to go offline on May 31, 2014, and moved Civilization 4, Warlords, Beyond the Sword and Colonization to Steamworks, later marking them "Online functionality has been successfully migrated". Shacknews reported the plan on Apr 22, 2014.

The update reached Steam on Jun 5, 2014. 2K's notice on Steam says the game "functions identically to the previous GameSpy version with the exception that the 'Direct IP' option has been removed", that saved games should not be affected, and that owners of a disc version could ask 2K support for the update. Since the game otherwise works as before, an online game still starts from the Multiplayer menu, with Steamworks in place of GameSpy. Whether 2K's Steamworks lobby is still fully working in 2026 has not been confirmed by 2K or the press; Steam's Civilization IV page still lists the game as multiplayer. Buying the game is covered on Complete Edition and Where to Buy.

Direct IP and the unsupported original release

Direct IP, which joined a game by typing the host's IP address and bypassed the lobby, was part of the original game, per the Civilization IV manual (p. 173). The Steamworks update removed it. Because players asked to keep it, 2K put the original GameSpy-era build on Steam as an unsupported beta branch named "Original Release - UNSUPPORTED", for PC only, chosen in the game's Properties under Betas, per an archived 2K Support article. That build has Direct IP but none of GameSpy's lobbies, which are gone. Patch 1.61's notes say multiplayer needs UDP port 2056 open on a firewall without an exception list, by Firaxis's patch notes.

LAN games

A LAN game is hosted and joined on a local network: the setup screen starts a new game or scenario or loads a save, and the list on the right shows every visible game on the network, per the Civilization IV manual (p. 172). After the first screens, players set up the game on a screen "just like the 'Custom Game' screen" (see Game Setup).

Hot Seat and Play by E-mail

Hot Seat puts every player on one computer: at the end of a turn the active player "will get up from the 'Hot Seat'" and lets the next one play, per the Civilization IV manual (p. 173). Play by E-mail is a Hot Seat game across machines in different places: after each turn the game state is sent to the next player, who sends it on. Patch 1.61 let a Hot Seat or e-mail host choose which civilization to play, allowed AI slots in player-made scenarios for these modes, and added an admin password to their staging screens, by Firaxis's patch notes. Neither mode needs an online service.

Turns, timers and teams

Internet and LAN games can be played with traditional turns or with simultaneous turns, in which everyone moves at once, with optional turn timers, per the Civilization IV manual (pp. 22 and 172). IGN's 2005 review welcomed the simultaneous format because you can "tinker with your cities" while others finish, and found a small, fast game could be done "in less than three hours".

Teams are made on the setup screen by giving civilizations the same team number. Teammates share sight, wonder effects, research, and victory or defeat, always have Open Borders and can never fight each other, per the Civilization IV manual (p. 170). Beyond the Sword added Simultaneous Team Turns, in which players on the same team take their turns at the same time, per its manual (p. 47).

Drops, saves and hot join

A game does not end when someone drops out. IGN's 2005 review describes the game telling the others a player has dropped and letting them wait for the player to rejoin or "let an AI opponent take over"; multiplayer games can be saved and resumed, and a civilization can be password-protected so nobody else takes it over when the game is loaded. Firaxis's feature list names hot join, taking over an AI civilization in a game already under way, among the multiplayer features.

Pitboss

Pitboss is a persistent turn-based server for long games: a "lightweight application" that keeps a game running while players log in, take their turns and log out, per the Warlords manual (pp. 105-109). It was not in the game at launch, which GameSpot's 2005 review counted against it; by Apr 13, 2006 2K's downloads page offered the PitBoss application beside patch 1.61, and Warlords shipped with it.

How a Pitboss game works, per the Warlords manual:

Joining: pick the Pitboss game in the LAN or Internet lobby (marked in the "PB" column) or connect to its IP address.
Waiting: when another player is logged out, you can take your own turn, then study the map and manage cities, but cannot move units until everyone has finished.
Reminders: the server can e-mail each player when a turn is ready, through an SMTP server the host enters.
Turn timer: set in hours, not minutes, and the same every turn; "typically 24 hours or so", and a player who misses it passes the turn.
Setup: a wizard chooses the mod, the e-mail settings, the network type (DirectIP, LAN or public Internet; the manual recommends DirectIP), a new game, scenario or save, and a staging room.
Admin screen: shows each player's connection and score; the host can kick a player, and the AI then takes over that civilization.

Mods and scenarios online

A mod or scenario can be played online only if every player loads the same one before entering the lobby: in Beyond the Sword, choose Advanced, then Load a Mod, wait for it to load, then Multiplayer, per its manual (p. 33). Versions must match exactly. Soren Johnson wrote in 2009 that groups trying Fall from Heaven online hit out-of-sync errors, because a synchronous game needs identical calculations on every machine. The mods themselves are on Mods, and the scenarios that shipped with each release on Scenarios.

Mac players

The Mac version by Aspyr offered LAN, Internet and e-mail games and could play against Windows players, by Macworld's report of Jun 19, 2006. The Mac listings on Steam did not get the Steamworks update, per 2K Support, and Steam's Civilization IV page now says the "Mac version's Online Multiplayer is no longer supported". Getting the game running on current systems is on Running Civilization 4 Today.

Colonization

Colonization, the standalone 2008 game on the same engine, has its own multiplayer menu with Internet, LAN (traditional or simultaneous turns), Play by E-mail and Hotseat, per the Colonization manual (p. 64), and 2K moved its online play to Steamworks along with Civilization 4's.

Frequently asked questions

Can you still play Civ 4 multiplayer online? Yes: since Jun 5, 2014 Civilization 4's online play runs on Steamworks instead of the closed GameSpy service, and 2K said the game works "identically" apart from the removed Direct IP option (2K on Steam). LAN, Hot Seat and Play by E-mail need no online service.

How do I get Direct IP back in Civ 4? Civilization 4's Steam version lost Direct IP in the 2014 Steamworks update; 2K offers the pre-Steamworks build as an unsupported beta branch, "Original Release - UNSUPPORTED", chosen under the game's Properties, Betas on PC (2K Support, archived).

Does Civ 4 have Hot Seat? Yes: Civilization 4's Hot Seat mode lets several players take turns on one computer, and Play by E-mail passes the game file between players in different places (manual, p. 173).

What is Pitboss in Civ 4? Pitboss is Civilization 4's persistent turn-based server: it keeps a game running so players can log in, take a turn and leave, with e-mail reminders and turn timers measured in hours; 2K offered it with patch 1.61 by April 2006, and Warlords shipped with it (Warlords manual, pp. 105-109).

When did GameSpy shut down for Civ 4? GameSpy's servers for 2K's games, Civilization 4 among them, closed on May 31, 2014, and the Steamworks update followed on Jun 5, 2014 (2K Support, archived).

Can Mac players play Civ 4 online? No longer: Steam's page for Civilization 4 says the "Mac version's Online Multiplayer is no longer supported" (Steam).

Can you play Civ 4 mods in multiplayer? Yes, if every Civilization 4 player loads the same mod first through Advanced, then Load a Mod, before entering the lobby (Beyond the Sword manual, p. 33).