Check for open ports on any domain or IP address to identify potential security vulnerabilities and service exposures.
Discover running services (HTTP, FTP, SSH etc.) and their versions behind each open port for comprehensive network analysis.
Identify unnecessary open ports that could be exploited, and get recommendations for strengthening your network security.
FAQs
What is an open port check?
An open port check scans a specific IP address or domain to identify which network ports are accepting connections, helping you assess potential security vulnerabilities or service availability.
How does your port scanner work?
Our tool sends TCP/UDP probes to specified ports and analyzes responses to determine status (open, closed, filtered). Scans are conducted from multiple global locations for accuracy.
Which ports can I check?
You can scan all 65535 ports, with quick-check presets for common ports (HTTP-80, HTTPS-443, SSH-22, etc.). We throttle scans to 100 ports/minute for free users.
Why would a port show as filtered?
Filtered means a firewall is blocking our probes without rejecting them. This differs from "closed" (rejected) and "open" (responding). Corporate networks often filter many ports.
Is port scanning legal?
Scanning your own systems is legal. Scanning others without permission may violate laws. We log all requests and restrict abusive behavior. Always get authorization before scanning networks you don't own.
Why do results differ from my local scans?
Differences occur due to: geographic firewall rules, ISP-level filtering, or network address translation (NAT). Our external scans show what's accessible from the internet.
Can I check UDP ports?
Yes, but UDP scanning is less reliable than TCP. Many UDP services require specific packets to respond, and firewalls often block unsolicited UDP traffic entirely.
How often should I scan my ports?
Monthly scans are recommended for most users. High-security environments should scan weekly or after any network configuration changes.
What's the difference between your tool and Nmap?
Our web-based tool offers quick external scans without installation, while Nmap provides deeper local network analysis. For comprehensive testing, we recommend using both.
Can I schedule automated port scans?
Yes, our monitoring service (premium feature) can schedule regular scans and alert you when new ports open or critical services become unavailable.