This is an old revision of the document!
General Port Forwarding Guide for People Who Want to Host NFS Underground
Before using this, look for a guide made for YOUR ROUTER MODEL, because it is usually better than a general guide!!!
I’m serious: start by looking for a guide for your router model on GOOGLE and YOUTUBE.
This is a general guide explaining the principle of port forwarding.
Every router is a little different, so you might need to check your router manual to find the exact menus for Port Forwarding, NAT, or Virtual Server.
Follow these steps carefully and you will be able to host NFS Underground.
Estimated Setup Time: 15–30 minutes
### Step 1 - Know the Game Ports
- NFS Underground uses UDP 3658 and 3659.
- UDP is a type of connection used for games; it is faster than TCP but less strict.
- Think of these ports as “doors” that allow other players to connect to your game.
—
### Step 2 – Make Sure Your PC Has a Fixed Local IP
- Your PC needs a fixed LAN IP, so the router always knows where to send game data.
- If the IP changes, port forwarding will fail.
Windows example:
1. Control Panel → Network and Internet → Network and Sharing Center → Change adapter settings
2. Right-click your network → Properties → Internet Protocol Version 4 (TCP/IPv4) → Properties
3. Select “Use the following IP address” and enter:
- IP: `192.168.1.100` (example)
- Subnet mask: `255.255.255.0`
- Default gateway: your router’s IP (usually `192.168.1.1`)
Linux example:
1. Network Settings → Wired/Wi-Fi → IPv4 → Manual
2. Enter: IP `192.168.1.100`, Netmask `255.255.255.0`, Gateway `192.168.1.1`
Tip: Pick an IP in the common range of your network (192.168.x.x) and avoid conflicts with other devices.
—
### Step 3 - Log Into Your Router
- Open a browser and type your router’s IP (usually `192.168.0.1` or `192.168.1.1`)
- Log in with the username/password from the router label or manual
- If you can’t find it, search online for your router model + “default login”
—
### Step 4 - Find Port Forwarding
- Look for Port Forwarding, Virtual Server, or NAT in the router menus
- This tells the router which ports should go to your PC
- If your router uses a special “Gaming” or “DMZ” menu, you can also check there
—
### Step 5 - Add the Game Ports
- Add a new rule for NFS Underground:
- Name: NFS Underground
- Protocol: UDP
- External port / Internal port: 3658–3659
- Internal IP: your PC’s fixed LAN IP (e.g., `192.168.1.100`)
- Save and apply the rule
Tip: Some routers require both “Start” and “End” ports; use 3658–3659 for both fields.
—
### Step 6 - Check Your PC Firewall
- Your firewall must allow NFS Underground to receive connections:
- Windows: Control Panel → System and Security → Windows Defender Firewall → Allow an app → Add NFS Underground → Make sure UDP 3658–3659 is allowed
- Linux: Use your firewall tool to allow UDP 3658–3659
Tip: Temporarily disable the firewall for testing if nothing works. Turn it back on afterward.
—
### Step 7 - Test Hosting
- Start NFS Underground and create a multiplayer game
- Ask a friend to join via the lobby
- If it doesn’t work:
- Double-check your LAN IP matches the one in the router
- Make sure ports 3658–3659 UDP are forwarded
- Check firewall settings
- If your ISP uses CGNAT (carrier NAT), normal port forwarding might not work. A VPS relay would be needed in that case which is easy to set up with Redhair's YouTube guide.
—
### Extra Tips for Beginners
- Always use a fixed LAN IP; changing IP breaks port forwarding
- Only forward the ports you need
- Test with 1-2 friends first before inviting many players
- Keep a note of your router login and port forwarding rules for future reference
- If unsure, take screenshots of each step to remember your settings