NapNodes
Free tool · Minecraft, Valheim and Project Zomboid

Is my port open?

You've forwarded the port on your router and don't know whether it worked. You can't tell from inside your own home: it has to be tested from outside. Pick the game, press “Test the port” and we'll try from our machine, the way a friend would connect. We only test the IP you open this page from.

Your public IP: checking…

Does your ISP use CG-NAT?

Log in to your router (often 192.168.1.1 or 192.168.0.1) and look on its status page for the “WAN IP”, “Internet IP” or “public IP”. Type it here and we'll compare it with the one we see from outside. It isn't sent anywhere.

What each result means

  • Open: it can be reached from the internet and something answers. For Minecraft we also tell you whether it's your server (with its version and players).
  • Reachable, but nothing there (TCP only): your connection answers, but no program is listening on that port. The forwarding is usually fine: start the server, make sure it listens on that port (in Minecraft, server-port in server.properties) and that the forwarding points to the right computer's local IP.
  • Closed: nobody answers. The router forwarding is missing, a firewall blocks it, or your ISP uses CG-NAT.
  • No reply (Valheim and Project Zomboid, which use UDP): with UDP we can only tell whether the game answers Steam's query. Test it with the server already running.

Each game's ports

If it shows as closed, in this order

  1. The server is running and listening on that port (its console shows the port when it starts).
  2. A fixed local IP for the server's computer (DHCP reservation on the router), so the forwarding doesn't end up pointing elsewhere.
  3. The forwarding rule on the router (“NAT”, “Port forwarding”, “Virtual server”): the port, the right protocol (TCP or UDP) and the computer's local IP.
  4. The firewall: Windows asks the first time the server starts; if you said no, add the inbound rule by hand. Your antivirus may have its own.
  5. CG-NAT: compare your router's WAN IP with the one above. If it's CG-NAT, forwarding can't work: ask your ISP for a public IP, use a tunnel or a gaming VPN (the options), or host the server outside your home.

Already open and want to see what your friends see? “Is my Minecraft server online?” shows the version, the MOTD and who's playing (also for Valheim and Project Zomboid).

Frequently asked questions

Why can't I test the port from my own home?

Because most routers don't let you come back in through your own public IP (so-called “NAT loopback” or “hairpinning”): even when the port is open, it looks closed from inside your network. It has to be tested from outside, like this tool does, or by a friend from their home.

Can I check another IP's port?

No. We only test the IP you open this page from, so nobody can use it against other people's machines. To see whether someone else's server is online, use the server status tools.

Why only ports from 1024 up?

The ones below are for system services (web, email, SSH…), not game servers. Minecraft's, Valheim's and Project Zomboid's are all above.

Does it work for Minecraft Bedrock or Hytale?

Not really: they use UDP and don't answer a query like Steam's, so from outside a closed port can't be told apart from an open one with nothing behind it. For them, the reliable test is a friend trying to join.

What is CG-NAT?

When your ISP shares one public IP between many customers. Your router has no public IP of its own, so port forwarding can't work: nobody outside reaches your home. You can tell because the router's WAN IP doesn't match the one shown above.

Do you store my IP or what I test?

No. The test runs at that moment and nothing is stored. We only count, in memory and for one minute, how many tests you run, to stop abuse (6 per minute). The CG-NAT comparison happens in your browser and isn't sent anywhere.

No router, no CG-NAT, your IP out of sight

A NapNodes server runs on our machines in the EU, with its own address: your friends join with it even when your PC is off, and your home IP stays hidden. There's a free one, no card needed, that starts when you want to play; if you want it running all the time, you move to a plan with the same world.

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