Port Scanner

Check open ports on any IP address online. Free port scanner to scan TCP/UDP ports, detect open, closed, and filtered states across common service ports or custom ranges.

Protocol
Ports (leave empty for default set)
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APIPOST /api/v1/network/ports
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Try also: Ping Test
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Key Features

100% Free

No registration required, unlimited checks

Instant Results

Real-time analysis with detailed output

REST API Access

Integrate into your workflow via API

Accurate Data

Live queries to authoritative sources

What is Port Scanner?

The port scanner probes network ports on a target IP address or hostname to determine which are open (accepting connections), closed (reachable but no service listening), or filtered (blocked by a firewall). You can scan common service ports — HTTP (80), HTTPS (443), SSH (22), FTP (21), SMTP (25), DNS (53), MySQL (3306), PostgreSQL (5432), RDP (3389) — or specify custom port ranges. Each open port represents a running network service that is accessible from the internet.

This free online port checker is used by system administrators verifying firewall rules after configuration changes, security professionals conducting authorized vulnerability assessments, DevOps engineers confirming that deployed services are reachable on expected ports, developers testing API and database connectivity, and network engineers troubleshooting connectivity issues. The scan is performed from our servers, giving you an external perspective on which ports are visible from the internet — which may differ from what you see when testing locally behind a firewall.

How to Use

  1. 1Enter the target IP address, domain name, or hostname you want to scan
  2. 2Select a preset port range (common ports, web ports, database ports) or enter specific port numbers
  3. 3Choose the protocol: TCP (default, connection-oriented) or UDP (connectionless)
  4. 4Click 'Run Check' to start scanning the specified ports
  5. 5Review results for each port: open (service accessible), closed (no service), or filtered (firewall blocking)
  6. 6Investigate any unexpectedly open ports — they may represent security risks or misconfigured services

Who Uses This

System Administrators

Monitor and troubleshoot infrastructure

Developers

Debug network issues and integrate via API

SEO Specialists

Verify domain configuration and performance

Security Analysts

Audit and assess network security

Frequently Asked Questions

Is port scanning legal?
Port scanning your own servers, networks, and infrastructure is completely legal and is a standard part of security management. Scanning systems you do not own requires explicit written authorization — unauthorized port scanning may violate computer security laws such as the CFAA (US), Computer Misuse Act (UK), or equivalent legislation in other countries. Authorized penetration testing, security audits, and network diagnostics are legitimate use cases. Always ensure you have permission before scanning any system you don't control.
What are the most commonly open ports and what services do they run?
The most frequently open ports on internet-facing servers include: 80 (HTTP — unencrypted web traffic), 443 (HTTPS — encrypted web traffic), 22 (SSH — secure remote shell access), 21 (FTP — file transfer), 25 (SMTP — email sending), 53 (DNS — name resolution), 110 (POP3 — email retrieval), 143 (IMAP — email retrieval), 3306 (MySQL — database), 5432 (PostgreSQL — database), 3389 (RDP — Windows remote desktop), and 8080/8443 (alternative HTTP/HTTPS ports). Each open port indicates a network service accepting connections on that port.
How do I check if a specific port is open on my server?
Enter your server's public IP address or hostname and specify the port number you want to check. Click Run Check and the tool will attempt a TCP connection to that port from our servers. If the port is open, a service is listening and accepting connections. If closed, the server responded but no service is running on that port. If filtered, a firewall is blocking the connection attempt. This external scan shows what the internet sees — if a port is open locally but shows as filtered here, your firewall is correctly blocking external access.
What is the difference between open, closed, and filtered ports?
An open port means a service is actively listening and accepting connections — this is expected for services you want to be accessible (web servers, email servers). A closed port means the host is reachable and responded to the probe, but no application is listening on that port — not a security concern. A filtered port means the probe received no response, typically because a firewall silently dropped the packet. Filtered is the most secure state for ports you don't want exposed. Ideally, only ports for your active services should be open; everything else should be filtered.
Why should I scan my server's ports regularly?
Regular port scanning helps detect unauthorized services that may have been installed by malware or misconfiguration, verify that firewall rules are working as intended after changes, confirm that only expected services are exposed to the internet, identify services running on non-standard ports that might be overlooked, and maintain a security baseline to quickly notice changes. Many security frameworks (PCI DSS, SOC 2, ISO 27001) require regular network scanning as part of compliance.

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API Endpoint

POST /api/v1/network/ports
View Documentation