Connection Host

The Connection Host, often shortened to Host, is the console that acts as a server during a Halo 2 or Halo 3 online Multiplayer match. The other consoles in the game are clients, and rely on the host for synchronization.

Background
Neither Halo 2 nor Halo 3 use dedicated servers -- that is, multiplayer matches in those games are not controlled from a server owned by Bungie or Microsoft. Dedicated servers for Halo 3 alone would be far too expensive; instead, a distributed networking model is used. In a distributed networking model, one Xbox keeps track of the game, and the other consoles rely on it to manage things like damage and spawns.

A host is needed because during a multiplayer match, things like lag and latency can cause the consoles involved in the game to "disagree". When such a disagreement occurs, the host's version of events is accepted by all consoles.

Usually, the player with the best connection ends up being the host. However, if a player with a superior connection joins the game after a host has been selected, then they will not become host. If, however, the current host lags out, then the newcomer will become host (assuming that their connection is still superior).

Example
Let's hypothesize that there are three players involved in an online multiplayer match: Person A, Person B, and Person C. Each player has their own console, and Person A is host.

Person A is running into a building with a window. Person B is firing a Rocket Launcher at them, and Person C is standing next to Person B while watching Person A. However, a minor network quirk occurs, and the three players' consoles end up disagreeing on what happened.
 * On Person A's console, A made it into the building. He took enough splash damage to drain his shields, but he is still alive.
 * On Person B's console, the rocket hit A, killing him instantly. Person B can see A 's corpse through the building's window.
 * On Person C's console, the rocket completely missed A, and his shields are full. Person C can see the unharmed Person A through the building's window.

A problem has been encountered: each of the consoles have a different version of events. The match cannot continue until this issue has been sorted out. How do the consoles reconcile their differing perceptions?

Person A's console is the connection host, so the consoles being used by Person B and Person C will automatically accept Person A 's version of events as being true. On Person B 's screen, A 's corpse will be replaced by an unshielded but living body; on Person C 's screen, A 's body will suddenly spark, as if its shields were drained.

Exploits
Among other things, the connection host can standby and, in some cases, view the IP addresses of other players. A player can forcibly earn host status by bridging.

Finding the Connection Host
Several glitches depend on synchronization (or desynchronization) with the host; such glitches may only work on the host console. The same applies to some mods. For modders and glitchers, methods of identifying the host can be quite useful.

There are several ways to identify the connection host.

Forge Method
This method is the easiest, but it will only work in Forge. Simply have everyone in the mach enter Edit Mode and look straight down. Have everyone return to Player Mode; the player that is still looking down is the connection host.

Equipment Method
This method can be used in Matchmaking. Grab any equipment item and walk up to an Overshield or Active Camo without actually touching it. Crouch, and walk to the powerup very slowly while holding RB. If you use the powerup, you are the connection host; otherwise, you will pick the powerup up as if it were a typical equipment item.

Theater Method
Simply bring a party to the Theater lobby. To view films, the host must be the party leader.

BR Method
The BR method involves the usage of a Battle Rifle and any secondary weapon. It may be performed at any time during a game.

Have the Battle Rifle out, and press R+R+Y. Two bursts (six bullets) will be heard coming out of the gun; then, you will switch to the secondary weapon. After that happens, switch back to the Battle Rifle. If it shows that one burst (three bullets) have been fired, then you are not the connection host. If it initially shows that two bursts were fired, but then quickly changes to show that only one burst has been fired, then you are not host. If it shows that two bursts were fired, and continues to show that two bursts were fired, then you are host.

Forcing the Connection Host
It's possible to force a person in the party to be the connection host.

Have everyone except the person who wants to be host leave the game and join back. When the current host leaves, a new host will be selected. Eventually, the person who wants to be host will be the only player left in the game, and they will become host (as they have the best, and only, connection). The game does not re-assign host status when the others join back, even if they have better connections.