Fix lag in Call of Duty

Lag in Call of Duty starts in one of three places: your home, your line or the route to Activision's servers. Find out which before you change anything or pay for a "ping reducer".

Run every check in one click Test server regions

In your home

Wi-Fi far from the router, other devices downloading, a busy PC or console, and strict NAT on the router. Test with the spike finder, then try a cable.

Find lag spikes

On your line

When someone uploads or streams, a queue builds in the router and your game waits behind it (bufferbloat). Smart Queue fixes it.

Fix bufferbloat

Beyond your line

Distance to the server and your provider's route. Pick the closest region, and check the route for detours below.

Test server regions

How Call of Duty picks a server

Call of Duty picks servers for you. Strict or moderate NAT limits who you can be matched with and can put you on further servers.

Settings worth checking

Settings → Interface → Telemetry: turn on Latency and Packet Loss.
Settings → Account & Network → Network: check the NAT type the game reports and aim for Open.
On PC, pause Battle.net or Steam downloads during matches.

Updates are huge. A console downloading the next patch in rest mode causes lag for everyone at home.

Ping to nearby server regions

Activision doesn't publish test addresses for its game servers, so this measures the cloud regions where most online games and voice chat run. It shows the lowest ping your connection can reach in each area and whether your provider takes a detour.

Ping to game and call servers

Round trips to the cloud regions where most game, voice and video servers run. Distance sets a floor on your ping that no setting at home can lower, so pick the closest region when a game lets you.

Call of Duty ports

Forwarding these fixes connection problems such as strict NAT or voice chat that won't connect. It doesn't lower lag on its own. Most routers with UPnP turned on open them automatically.

Protocol	Ports
TCP	3074, 27014–27050
UDP	3074–3079, 3478, 4379–4380, 27000–27031, 27036

On consoles, Xbox Live uses TCP 3074 and UDP 88, 500, 3074, 3544, 4500; PlayStation Network uses TCP 3478–3480.

As listed by Activision; they can change, so check Activision support if something doesn't work. Test a forward with the port checker.

Pause downloads while you play Check this device for stutter