Open Port Checker
An open port checker instantly tests whether a specific TCP port on a website or server is open (listening) or closed (filtered). Open ports are potential entry points for attackers — knowing which ports are exposed is step one of any security audit.
Related Port Scanning Tools
Common Ports & Their Security Risk
| Port | Service | Risk Level | Notes |
|---|---|---|---|
| 22 | SSH | ⚠️ Medium | OK if needed, restrict to known IPs |
| 23 | Telnet | 🔴 Critical | Unencrypted — disable immediately |
| 80 | HTTP | 🟢 Low | Expected for web servers |
| 443 | HTTPS | 🟢 Low | Expected — ensure TLS is current |
| 3306 | MySQL | 🔴 Critical | Database — never expose to internet |
| 3389 | RDP | 🔴 Critical | Most attacked port on internet |
| 5432 | PostgreSQL | 🔴 Critical | Database — close or firewall |
| 6379 | Redis | 🔴 Critical | Often exposed without auth — check now |
| 27017 | MongoDB | 🔴 Critical | Leaked millions of records historically |
| 8080 | HTTP Alt | ⚠️ Medium | Dev servers often exposed accidentally |
Frequently Asked Questions
How do I check if a port is open?
Enter the hostname or IP address and the port number into VulnScan's open port checker. The tool attempts a TCP connection and reports back "OPEN" (connected) or "CLOSED/FILTERED" within seconds.
Which ports should be open on a web server?
Port 80 (HTTP), 443 (HTTPS), and 22 (SSH, if needed) are typical. All other ports should be closed or firewalled. Open database ports (3306 MySQL, 5432 PostgreSQL, 27017 MongoDB) are major security risks.
Is it safe to have any open ports?
Open ports are necessary for services to function, but unnecessary open ports dramatically increase your attack surface. Each open port should have a specific business purpose, run up-to-date software, and be protected by a firewall.