Ports
Port Checker
Check whether a port is open and reachable from the Internet.
ResultOpen or closed status
Guides
Port Forwarding: Setup and Troubleshooting
How to let a service on your home network be reached from the Internet — and what to check when the port still shows closed after you have forwarded it.
Written by the Pingvero team · Last updated October 6, 2026
The Basics
What Port Forwarding Does
Your router gives every device on your network a private address and shares a single public IP address with the Internet. Connections you start go out without trouble, but an incoming connection has nowhere to go: the router doesn’t know which device it is meant for.
Port forwarding is a rule that tells the router: when a connection arrives at this port, send it to that device. It is how a game server, a security camera, a home web server or a remote-access tool becomes reachable from outside. If you are new to port numbers, the common ports list explains what each one is for.
Setup
How to Set Up Port Forwarding
Menu names differ between routers, but the steps are the same. Look for “Port Forwarding”, “Virtual Server” or “NAT” in the router’s settings.
Find the device’s local IP address (for example
192.168.1.50) in its network settings, and make it permanent: set a DHCP reservation in the router, or a static address on the device. If it changes later, the rule stops working.Decide the port and protocol. Use the port your service listens on, and TCP or UDP as the service requires. When unsure, the common ports list shows the default for most services.
Log in to the router (its address is usually printed on the device, often
192.168.1.1or192.168.0.1) and open the port forwarding page.Create the rule: external port, internal port (normally the same), protocol, and the device’s local IP address. Save it, and restart the router if it asks.
Allow the port in the device’s own firewall, and make sure the service is running and listening on that port.
Test from outside your network — see the next section. Testing from a device on your own Wi-Fi often fails even when the rule is right.
Verify
How to Test That the Port Is Open
The test has to come from outside your network, because that is the view the rest of the Internet has. Pingvero’s Port Checker connects from its own server: enter your public IP address (the Use my IP button fills it in), the port and the protocol.
An open result means the connection completed. Closed means it was actively refused, and filtered means nothing came back. Which of the two you get is a useful clue, as the checklist below shows.
Troubleshooting
Port Forwarding Not Working? Work Through This List
Start at the top: the checks are ordered from the most common cause to the least.
| What you see | Likely cause | What to check |
|---|---|---|
| Works from outside only sometimes, or stopped after a restart | The device’s local IP address changed. | Set a DHCP reservation or a static address, then update the rule. |
| Closed (refused) | Nothing is listening on that port, or it is the wrong port or protocol. | Confirm the service is running and which port it listens on; check TCP vs UDP. |
| Filtered (no response) | A firewall is dropping the connection, or the router rule is not applied. | Allow the port in the device firewall; recheck the rule’s IP, port and protocol. |
| Works on your Wi-Fi, fails from outside | You tested with your internal address, or the router lacks NAT loopback. | Test with your public IP from outside your network, for example with the Port Checker. |
| Rule is correct, still filtered | Your ISP blocks the port, or you are behind CGNAT. | Try another port number; compare your router’s WAN IP with your public IP (next section). |
| Worked yesterday, fails today | Your public IP address changed. | Re-check your IP with What Is My IP, or use a dynamic DNS name. |
The Hidden Cause
Are You Behind CGNAT?
Many ISPs now put several customers behind one shared public IP address, a setup called carrier-grade NAT (CGNAT). If you are behind it, no rule on your own router can work, because incoming connections never reach your router at all.
How to check: open your router’s status page and read the “WAN” or “Internet” IP address. Then look at your public IP on What Is My IP. If the two differ, or if the router’s address starts with 10., 192.168., 172.16–172.31 or 100.64–100.127, you are behind CGNAT. (The 100.64.0.0/10 block is reserved for this purpose — see RFC 6598.)
What you can do: ask your ISP for a public IPv4 address (some charge for it), check whether your connection also has IPv6, or use a VPN or tunnelling service that provides inbound ports.
Stay Safe
Is Port Forwarding Safe?
- Forward only the ports you need, and remove rules you no longer use
- Keep the service you expose updated, with strong, unique credentials
- Never forward remote desktop, databases or file sharing directly — use a VPN instead
- Re-run the Port Checker after changes to confirm only what you intended is open
The common ports list marks which ports are normally public services and which should stay private.
FAQ
Port Forwarding FAQ
Short answers to the questions people ask most about port forwarding.
Why is my port still closed after port forwarding?
The usual causes are, in rough order of likelihood: the rule points at the wrong local IP address (it changed), the device’s own firewall is blocking the port, nothing is listening on that port, your ISP shares one public IP between customers (CGNAT) or blocks the port, or you tested from inside your own network. The checklist above walks through each one.
Do I need a static IP address to forward a port?
The device you forward to needs a local IP address that does not change, because the rule points at that address. Set a DHCP reservation in the router or a static address on the device. Your public IP can change too; if it does, use a dynamic DNS name instead of the raw address.
What is CGNAT and why does it break port forwarding?
With carrier-grade NAT (CGNAT) your ISP puts many customers behind one shared public IP address. Forwarding a port on your own router cannot help, because incoming connections never reach it. Ask the ISP for a public IP address, check whether you also have IPv6, or use a VPN or tunnel that offers inbound ports.
Is port forwarding safe?
It exposes whatever is listening on that port to the whole Internet, so it is as safe as that software. Forward only the ports you need, keep the service updated and protected with strong credentials, and prefer a VPN for remote administration, databases and remote desktop.
Get started
Check Whether Your Port Is Open
Run the free Port Checker to see what the Internet sees on your connection right now.