Port Check Tool
Test if ports are open or closed • Verify firewall rules • Check network connectivity
Bulk Port Scanner
Quick Scan Presets
Professional Port Check & Scanner Tool
Our Port Check Tool is a free online port scanner designed for network administrators, developers, and IT professionals. Test port connectivity, verify firewall configurations, and diagnose network issues instantly with support for both TCP and UDP protocols.
What is Port Checking?
Port checking (or port scanning) is the process of testing network ports on a host to determine which ports are open, closed, or filtered by a firewall. Ports are virtual endpoints for network communication, with each port number associated with specific services or protocols. Understanding port status is essential for network security, troubleshooting, and service deployment.
Why Use Our Port Checker?
Common Ports & Services
Here are the most commonly checked ports and their associated services:
Port 80TCPHTTP - Web Server
Port 443TCPHTTPS - Secure Web Server
Port 22TCPSSH - Secure Shell
Port 21TCPFTP - File Transfer
Port 3306TCPMySQL Database
Port 3389TCPRDP - Remote Desktop
Port 25TCPSMTP - Email Server
Port 53UDP/TCPDNS - Domain Name System
Features of Our Port Scanner
- ✓Instant Results: Real-time port status checking with no delays
- ✓TCP & UDP Support: Test both TCP and UDP protocol ports
- ✓Domain & IP Support: Check ports on domain names or IP addresses
- ✓Common Ports Database: Quick access to frequently used ports
- ✓Custom Port Testing: Test any port from 1 to 65535
- ✓Service Identification: Automatically identify services running on ports
- ✓100% Free: No registration required, unlimited checks
Understanding Port Status
🟢 Open
The port is accessible and accepting connections. A service is actively listening on this port.
🔴 Closed
The port is reachable but no service is listening. The host responded but refused the connection.
🟡 Filtered
Cannot determine if the port is open or closed. Likely blocked by a firewall or network filter.
⚫ Timeout
The connection attempt timed out. The host may be down or unreachable.
Common Use Cases
- • Web Server Testing: Verify HTTP (80) and HTTPS (443) ports are accessible
- • Remote Access: Test SSH (22) or RDP (3389) connectivity before connecting
- • Database Access: Check if database ports (3306, 5432, 1433) are open
- • Email Server: Verify SMTP (25), POP3 (110), and IMAP (143) ports
- • Gaming Servers: Test game server ports for multiplayer connectivity
- • Port Forwarding: Verify router port forwarding configurations
- • Security Audits: Identify unnecessarily open ports on servers
- • VPN Setup: Test VPN ports (1194, 1723) for proper configuration
Frequently Asked Questions
Is port scanning legal?
Port scanning your own systems or networks is legal. However, scanning systems you don't own without permission may violate computer fraud laws. Always obtain proper authorization before scanning external systems.
What's the difference between TCP and UDP?
TCP (Transmission Control Protocol) is connection-oriented and guarantees packet delivery, making it ideal for web traffic and file transfers. UDP (User Datagram Protocol) is connectionless and faster but doesn't guarantee delivery, used for streaming and gaming.
Why is my port showing as filtered?
A filtered status typically indicates a firewall is blocking the connection attempt. Check your firewall rules, router settings, or contact your hosting provider to ensure the port is not being blocked.
How can I open a closed port?
To open a port, you need to configure your firewall to allow traffic on that port and ensure a service is running and listening on it. You may also need to set up port forwarding on your router for external access.