Port Scan Online — Free Network Port Scanner
Running a port scan online is the fastest way to see what network services are exposed on a website or server — from an external attacker's perspective. VulnScan's online port scanner connects from our infrastructure to your target, testing common ports and flagging risky ones.
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
What is an online port scan?
An online port scan tests which TCP/UDP ports on a server are open (accepting connections) from the public internet. Unlike local scans, an online port scan shows exactly what an outside attacker sees — giving you the most accurate security picture.
Which ports does the online scanner check?
VulnScan checks 20+ common ports including: 21 (FTP), 22 (SSH), 23 (Telnet), 25 (SMTP), 53 (DNS), 80 (HTTP), 110 (POP3), 143 (IMAP), 443 (HTTPS), 445 (SMB), 1433 (MSSQL), 3306 (MySQL), 3389 (RDP), 5432 (PostgreSQL), 6379 (Redis), 27017 (MongoDB).
Is it legal to port scan a website?
It is legal to port scan websites you own or have explicit authorization to test. Port scanning third-party websites without permission may violate the Computer Fraud and Abuse Act (CFAA). VulnScan is designed for security testing your own infrastructure.