PZ Port Forwarding: Ditch Lag, Keep Zombies Out

Quick Answer

Yes – if you want friends to join your Project Zomboid game, you'll need to open UDP port 16261 on your router (and ideally UDP port 16262 as well). Without proper port forwarding, external players cannot connect to your server or will experience lag due to Steam relay fallbacks.

Table of Contents

Introduction: Why Port Forward?

When you host a Project Zomboid game, your PC acts as a server. By default, your router blocks outside traffic from reaching that server for security reasons. Port forwarding punches a hole through your router's defenses for specific network ports, allowing your friends (or anyone you invite) to connect to your Project Zomboid server from the internet.

Without forwarding the correct ports, players won't be able to join – or they'll be forced through slower relay connections. If you're planning to run a more permanent server setup, you'll also want to check out our comprehensive server administration guide for advanced configuration tips. Let's get your ports open and your server thriving!

Quick-Start: Five Steps to Multiplayer

1. 1
   Find Your Server's Local IP: On the PC hosting the game, find its LAN IP address. On Windows, press Win+R, type cmd, then run ipconfig. Look for the IPv4 address (e.g., 192.168.1.100). This is the address your router will forward ports to.
2. 2
   Log Into Your Router: Open a web browser and enter your router's gateway IP (common ones are 192.168.1.1 or 192.168.0.1). Sign in with admin credentials. (If unsure, check your router's label or manual for the login URL, username, and password.)
3. 3
   Create Port Forward Rules: In your router's settings, locate Port Forwarding (sometimes under "Advanced" or "NAT/PAT"). Add new rules forwarding:

   • Port 16261 UDP to your PC's IPv4 address (main game port)
   • Port 16262 UDP to the same IP (player connections)
   • (Optional) Forward UDP 8766 for server listing visibility
   • Set Protocol to UDP (or "Both/UDP+TCP" if that's your only option)
4. 4
   Open Firewall & Launch Server: Ensure your PC's firewall isn't blocking the game. The first time you host, Windows may prompt "Allow access" – choose Allow on private/home networks. Start your Project Zomboid server (either "Host" in-game or launch the dedicated server).
5. 5
   Test the Connection: Have a friend try to join using your public IP + port (find your public IP on icanhazip.com). Alternatively, use the Steam "Invite Friend" feature if hosting via the game's Host button.

A Note on Build 42 Unstable (B42)

At the time of writing (2025-06-24), Build 42's multiplayer is disabled during testing. If you're on the B42 unstable branch, you cannot host or join MP games yet. Stick to Build 41 for multiplayer. For more details on switching between builds and understanding the differences, check out our Build 41 vs 42 server guide. Once B42 MP is enabled (likely with similar port requirements as B41), you'll use the same port forwarding steps described here.

Understanding Project Zomboid Networking (B41 Basics)

Before messing with router settings, it helps to know which ports Project Zomboid uses and why. Here's a quick breakdown:

Steam Relay vs. Direct Connection

Project Zomboid uses Steam's networking to simplify co-op. If ports aren't properly forwarded, the game will attempt to use Steam's relay service as a fallback. While this often works for small co-op sessions, it can introduce higher latency and bandwidth limitations.

The game prefers direct UDP connections to your machine if available. If it can't reach you directly (no port forwarded), you'll see the "port 16262 closed" warning on the client side.

Think of Steam Relay as a helpful backup – it can punch through some firewalls automatically, but if you want optimal performance, or if you're running a persistent server, setting up port forwarding is worth the few minutes of effort.

Setting Up Port Forwarding on Your Router

1. Reserve or Set a Static Local IP

Before creating forwarding rules, ensure your host computer's local IP stays constant. By default, your router's DHCP may change your PC's IP over time. If that happens, the port rule would point to the wrong device.

You have two options:

• Reserve an IP in the router's DHCP settings: Most routers allow mapping a specific IP to your PC's MAC address (often under "DHCP Reservation" menu).
• Set a static IP on your PC: Manually assign an IP in your computer's network adapter settings (make sure it's in the same subnet as the router).

2. Access the Router's Port Forwarding Menu

Log in to your router's web interface (usually by navigating to its local IP in a browser). Once you're in, find the section for Port Forwarding. This might be under:

• Advanced Settings > Port Forwarding/Port Triggering (common on Netgear).
• Firewall > Virtual Servers (on some TP-Link and D-Link models).
• NAT > Port Forwarding (on some ASUS, often under WAN settings).
• A dedicated Port Forwarding tab or menu.

Add a new port forward rule and you'll typically need to input:

• Service Name: Description – e.g., "Project Zomboid Server"
• Port Range: External/Internal – e.g., start 16261, end 16261
• Protocol: Choose UDP (or "UDP/TCP" or "Both" if UDP-only isn't an option)
• Internal IP: The local IP of your server PC (e.g., 192.168.1.100)

3. Verify the Ports Are Open

With rules in place and your server running, you can test if your port is reachable using an online port checker tool. However, many online tools don't check UDP ports reliably.

The best test is to have a friend attempt to connect, or use the Steam "Add Server by IP" function.

Brand-Specific Port Forwarding Tips

Configuring Firewalls & Antivirus

Even after you've convinced your router to let players in, local firewalls on the host PC can slam the door shut. You need to allow Project Zomboid server traffic through your computer's firewall.

Windows Firewall (Defender)

When you first run a Project Zomboid server, Windows should pop up a dialog asking you to allow the app through the firewall. Click "Allow Access" and ensure at least the Private network box is checked.

If that dialog never appeared, you may have to set rules manually:

1. Open Windows Firewall with Advanced Security (search "Firewall" in start menu)
2. Go to Inbound Rules, and click "New Rule…"
3. Choose Port. Select UDP and enter 16261-16262 as Specific Ports
4. Allow the connection. Select the network profiles (Private/Home is most important)
5. Give it a name like "PZ Server UDP Ports" and finish

Linux Firewall (ufw/iptables)

On Linux, if you're running a dedicated server, you'll need to allow the ports via your firewall settings:

On headless servers, also ensure any cloud provider firewall (like AWS security groups, Azure NSGs) have these UDP ports open.

Antivirus / Third-Party Suites

If you use a third-party antivirus or internet security suite (Norton, McAfee, etc.), they sometimes have their own firewalls. Make sure to allow the Project Zomboid server through those as well.

Running Co-op vs. Dedicated Servers

Project Zomboid offers two multiplayer hosting methods, and it's useful to understand how port forwarding applies to each:

Troubleshooting Common Issues

Advanced Tips & Tools