One console = one online player at a time. CoD4 uses a single profile sign-in; second controller can only join local split-screen (offline or System Link).
| Setup | Online Together? | How |
|---|---|---|
| 1 Console, 2 Controllers | No | Split-screen private match / System Link only |
| 2 Consoles, 2 Accounts, 1 Internet | Yes | Each console signs in separate profile; NAT Open required |
| 2 Consoles, 1 Account | No | Account can only be active on one console |
Xbox 360 servers still up (2024) but peer-to-peer host migration causes lag. Backward compatible on Xbox One/Series — same restrictions apply.