Free Port Check — Open Port Scanner

A port check tells you whether a specific port on a server is open (accepting connections), closed (actively refusing connections), or filtered (blocked by a firewall). VulnScan's free port check tool scans any IP address or domain across 1,000+ common ports.

Every open port is a potential attack surface. Knowing exactly which ports are exposed helps you enforce a strict firewall policy and minimize risk before attackers can exploit it.

Common Ports to Check

• Port 22 (SSH) — Remote admin access — should be restricted by IP only
• Port 80/443 (HTTP/HTTPS) — Web traffic — typically the only ports that should be open publicly
• Port 3306 (MySQL) — Database — must NEVER be publicly accessible
• Port 5432 (PostgreSQL) — Database — must NEVER be publicly accessible
• Port 27017 (MongoDB) — Database — must NEVER be publicly accessible
• Port 3389 (RDP) — Windows Remote Desktop — major ransomware entry point
• Port 21 (FTP) — Insecure file transfer — replace with SFTP (port 22)
• Port 8080/8443 — Alternative HTTP/HTTPS — often exposed unintentionally
• Port 6379 (Redis) — Cache — frequently exposed with no auth, leading to data theft
• Port 9200 (Elasticsearch) — Search index — often publicly accessible with no auth

What Happens When the Wrong Port is Open?

Automated scanners and bots run port checks against every IP address on the internet 24/7. Within minutes of a server coming online, attackers know exactly which services are running. An exposed database port (3306, 5432, 27017) is scanned within 4 minutes of going live on the internet.

What is a port check?

A port check is a test that determines whether a specific TCP or UDP port on a server is open (accepting connections), closed, or filtered by a firewall. It's the first step in understanding your server's attack surface.

How do I check if port 80 is open?

Enter your domain or IP address in the VulnScan scanner above. Our free port check will automatically test port 80 (HTTP), 443 (HTTPS), and hundreds of other common ports. Results appear in seconds with no signup required.

What ports should be open on a web server?

Typically only ports 80 (HTTP) and 443 (HTTPS). Everything else should be firewalled or restricted to specific IP addresses. SSH (port 22) should be locked down to a specific management IP.

Is port scanning legal?

Scanning your own servers is always legal. Scanning servers you don't own without permission may violate computer fraud laws in your country. VulnScan is designed for scanning your own infrastructure and websites.

Why is an exposed database port dangerous?

Open database ports (3306 MySQL, 5432 PostgreSQL, 27017 MongoDB) allow attackers to attempt brute-force authentication directly. Bots scan all internet-facing IPs continuously. An exposed database port is often compromised within hours.

Every day you wait is another day hackers have the advantage

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