Ports & Connectivity
Port Checker: Test if a TCP Port Is Open or Closed
Open ports are required for servers, games, and applications to accept incoming connections. Our port checker tests whether a specific TCP port on any host is open and accepting connections, helping you verify firewall rules, server configurations, and NAT settings.
Launch in Mission ControlWhat It Measures
This tool attempts to establish a TCP connection to the specified host and port, reporting whether the port is open (accepting connections), closed (connection refused), or filtered (connection timed out, typically blocked by a firewall). It also measures connection time.
How It Works
- Takes a hostname or IP address and port number as input
- Attempts a TCP handshake to the specified endpoint
- Interprets the response: SYN-ACK (open), RST (closed), or timeout (filtered)
- Reports status and connection time in milliseconds
Why It Matters
Port testing is essential when setting up game servers, web servers, VPN endpoints, or any service that needs to accept incoming connections. It immediately tells you whether your firewall rules and port forwarding are working correctly without requiring you to connect from another location manually.
Understanding Your Results
A port should respond as expected for its intended purpose: open for services you want accessible, filtered or closed for everything else. Connection time to an open port should match your network latency to the host. Timeouts on ports that should be open indicate a misconfigured firewall or router.
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Run Port Checker Now →Frequently Asked Questions
What is the difference between an open, closed, and filtered port?
An open port responds with a SYN-ACK, indicating a service is listening and ready to accept connections. A closed port sends RST (reset), indicating the host is reachable but no service is listening on that port. A filtered port times out, typically because a firewall is blocking the probe before it reaches the host.
How do I open a port on my router?
Log into your router's admin interface (usually 192.168.1.1 or 192.168.0.1) and find the Port Forwarding or NAT section. Add a rule specifying the external port, the local IP address of your device, and the internal port. The device's local IP should be set as a static IP or a DHCP reservation.
What ports are commonly used for gaming?
Common gaming ports include 3074 (Xbox/Call of Duty), 3478 and 3479 (PlayStation), 7777 to 7780 (Minecraft), 25565 (Minecraft Java), and 27015 to 27030 (Steam games). Game-specific requirements are listed in each game's documentation or the publisher's support pages.
Can I check ports on my own IP address?
Yes, you can check ports on your public IP to see what is accessible from the outside internet. This is useful for verifying that a service you host is reachable externally or confirming that sensitive ports are properly blocked. It shows exactly what an external user sees when connecting to your IP.
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