How to port forward a Project Zomboid server
Zomboid needs its default port and the one directly above it, both on UDP. Steam-listed servers additionally use two fixed Steam ports, but those are only about appearing in the public list.
Your setup
Pick the firmware family, not the exact model — the menus are identical across a range.
Default is 16261. If you changed it, it is the value of DefaultPort in the server .ini.
The private address of the machine running the server — ipconfig on Windows, ip addr on Linux. It starts with 192.168, 10. or 172.
Open these
This firmware accepts ranges, so each line below is a single rule.
- 16261-16262 UDP
16261UDPGame trafficDefaultPort. Direct connections land here.16262UDPPlayer channelUDPPort. Build 41 opens a second port immediately above the first; without it players connect and then hang on "Initialising".
Only if you want them
The server works without these. Every port you open is a port someone can knock on, so skip anything you do not need.
- 8766-8767 UDP
8766UDPSteam queryOnly for Steam-listed servers.8767UDPSteam masterPairs with 8766 for the public list.
Do not open these
This game has no remote-administration port to get wrong. Forward only what is listed on the left and nothing else.
Step by step: your router
- 1
Give the server a fixed local IP
A forward points at one address. If the server picks up a different one after a reboot, the rule silently starts pointing at nothing — this is why forwards "stop working" on their own.
On this router:look for DHCP Reservation, Address Reservation, Static Lease or Manually Assigned IP
- 2
Open the router admin page
Try these addresses in a browser on the same network:
- 192.168.0.1
- 192.168.1.1
- 192.168.2.1
- 10.0.0.1
Almost always printed on a sticker on the router itself.
- 3
Find the port forwarding page
Port Forwarding, Virtual Server, NAT, Applications & Gaming, or Port Mapping
Vendors use at least six names for the same feature. Whatever it is called, the page you want is the one asking for a port, a protocol and a device on your network. If the external and internal port fields both exist, set them to the same number.
- 4
Create one rule per line
a description field, if there is one External / WAN / Public / Service port Internal / LAN / Private port Protocol Internal IP / Device / Server IP Project Zomboid 16261-16262 16261-16262 UDP your server’s local IP External and internal port are the same number here. Changing the external port is possible, but then everyone connects on the new one, so keep them matched unless you have a reason.
- 5
Let the server through its own firewall
The router now sends traffic to the machine, and the machine can still refuse it. Windows Defender Firewall in particular blocks a freshly installed dedicated server by default, which looks exactly like a failed forward.
Take it with you
Project Zomboid — port forwarding rules --------------------------------------- 16261-16262 UDP -> <server local IP>
Check whether it worked
Test from outside your own network. Connecting from a machine in the house proves nothing — that traffic never leaves the LAN and never touches the rule you just wrote.
What usually goes wrong
Forwarding only the first port produces the single most recognisable failure in Zomboid hosting: players connect, the handshake completes, and then the client sits on "Initialising" forever. It is not a mod conflict and it is not a slow world load. It is the second port, which the server uses for the actual player channel once the connection is established.
Not forwarding at all
Zomboid servers are memory-hungry in proportion to how far your players have explored, because the server keeps loaded chunks resident. A long-running world outgrows a spare desktop faster than most people expect.