Port Checker

Introduction to Port Checker

Port Checker is an online utility for assessing the status of network ports on a specified IP address or hostname. It reports whether each tested port is open, closed, or filtered, and supports checks over TCP and UDP for both IPv4 and IPv6.

Designed for network administrators, developers, IT operations teams, and individuals who manage remote hosts or game servers, the tool helps validate port forwarding, confirm service availability, and troubleshoot connectivity issues without installing software or creating an account.

Key Takeaways

• Browser-based port status testing (open, closed, filtered)
• Supports TCP and UDP on IPv4 and IPv6
• Automatic public IP detection with optional hostname input
• Test from selectable locations (e.g., United States, United Kingdom, Germany, India)
• Version Scan identifies listening services and software versions on open ports
• Bulk checks via comma lists and ranges; category presets for server, game, application, and P2P ports
• Quick verification of router port forwarding; no login or signup required

How Port Checker Works

Use the auto-detected public IP address or enter any IPv4/IPv6 address or hostname. Specify one or more ports using comma-separated lists (e.g., 80, 443) and/or ranges (e.g., 1-49). Choose the protocol (TCP or UDP), optionally enable Version Scan, and select a test location to validate external reachability from different regions.

When you start the check, the tool probes each specified port and reports individual results. Outcomes indicate open, closed, or filtered status. When available, the tool maps common services to their port numbers and, with Version Scan enabled, reports detected software and version (for example, HTTPS on 443 running Apache HTTP Server 2.4.41).

Core Benefits and Applications

• Verify port forwarding: Confirm that router rules expose the intended service (e.g., Minecraft server on 25565).
• Troubleshoot firewall issues: Identify whether a local, router-level, or ISP-level firewall is blocking access (e.g., RDP on 3389).
• Check service availability: Validate that essential services are listening and reachable (e.g., HTTP 80, HTTPS 443, SSH 22).
• Test network configurations: Confirm NAT, VPN, and server setups are functioning as expected (e.g., custom app on port 9000).
• Detect ISP restrictions: Identify blocked ports and select alternatives (e.g., use 8080 when 80 is restricted).
• Improve security posture: Find unnecessary open ports (e.g., Telnet 23) and reduce exposure.