PF Port Checker

Scan and check open ports on any host with this free online PF port checker tool.

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About This Tool

The PF Port Checker is a comprehensive online tool that allows you to scan and check the status of ports on any host or IP address. Enter a hostname or IP address along with port numbers or ranges to perform TCP and UDP port scans. The tool displays detailed results including port status (open, closed, filtered), service detection, and response times. Perfect for network administrators, developers, and security professionals to test firewall configurations, verify service availability, and troubleshoot network connectivity issues.

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How to Use

Enter the target hostname or IP address in the 'Host' field\n
Specify ports to scan (single port, comma-separated list, or range like 80-
\n
Select scan type (TCP or UDP)\n
Set timeout value (default 2 seconds)\n
Click 'Scan Ports' button to start the scan\n
View results showing port status, service, and response time\n
Use 'Clear' button to reset the form or 'Export Results' to save scan data

Frequently Asked Questions

Find Quick Answers

What is a port checker and how does it work?

A port checker is a network tool that tests whether specific ports on a host are open, closed, or filtered. This tool works by attempting to establish TCP connections or send UDP packets to the specified ports and analyzing the responses to determine port status.

Is port scanning legal?

Port scanning your own servers or devices you have permission to test is legal. However, scanning networks or systems you don't own or have explicit authorization for may violate laws and terms of service. Always ensure you have proper authorization before scanning any network.

What's the difference between TCP and UDP port scanning?

TCP scanning establishes a full connection handshake (SYN, SYN-ACK, ACK) to determine port status. UDP scanning sends datagram packets and analyzes responses; it's less reliable as many UDP services don't respond to unsolicited packets. TCP is more accurate for most common services.

Why are some ports shown as 'filtered'?

A 'filtered' status means the port is protected by a firewall or security device that is dropping or rejecting connection attempts without responding. This prevents the scanner from determining if a service is actually running on that port.

How many ports can I scan at once?

You can scan individual ports, multiple ports (comma-separated), or port ranges. For performance and security reasons, we recommend scanning no more than 100 ports at a time. Large scans may take longer and could trigger security alerts on the target system.

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