Open Port Checker

Check which ports are open on any IP address. Open ports can expose services to the internet and may pose security risks if not properly secured.

Enter an IPv4 address below and click Check Ports to see a list of open ports, running services, detected vulnerabilities, and associated hostnames — powered by Shodan InternetDB.

What Are Open Ports?

A port is a communication endpoint used by network protocols like TCP and UDP to distinguish between different services running on the same device. When a port is "open," it means a service is actively listening for incoming connections on that port.

Open ports are essential for network communication — web servers listen on port 443 (HTTPS), email servers use port 25 (SMTP), and so on. However, unnecessary open ports can expose your system to attacks.

Common Port Numbers & Their Services

How does this tool work?

This tool queries the Shodan InternetDB, a free API that provides summary information about IP addresses including open ports, hostnames, software (CPEs), vulnerabilities (CVEs), and tags. The data is collected by Shodan's global network of crawlers and is updated weekly.

Unlike active port scanning, this tool uses passive lookup — it retrieves previously observed data rather than probing the target in real time. This means:

• Results reflect the most recent Shodan scan, not the current live state
• No packets are sent to the target IP during your query
• Some recently opened or closed ports may not yet be reflected

Why should I check open ports?

• Security auditing — Identify unexpected open ports that may expose vulnerable services
• Server hardening — Verify that only intended services are accessible from the internet
• Incident response — Quickly assess what an IP address was exposing when compromised
• Compliance — Ensure your infrastructure meets security baseline requirements

How to secure open ports

1. Close unused ports — Disable services you don't need or bind them to localhost only
2. Use a firewall — Block incoming traffic on ports that shouldn't be publicly accessible
3. Keep software updated — Patch known vulnerabilities in services running on open ports
4. Use encryption — Replace plain-text protocols (HTTP, Telnet, FTP) with encrypted alternatives (HTTPS, SSH, SFTP)
5. Implement access controls — Restrict access to sensitive services using IP allowlists or VPNs