Why use a Port Checker?
A port scanner allows you to test whether a specific TCP port is open and actively listening on a remote server. This is a fundamental security practice for system administrators. Hackers frequently scan public IPs looking for vulnerable services left open by mistake.
Common ports that should generally be protected by a firewall include:
- Port 22 (SSH): Secure Shell access. Should ideally be restricted to known IPs.
- Port 3389 (RDP): Remote Desktop Protocol. Extremely vulnerable to brute-force ransomware attacks if exposed publicly.
- Port 3306 (MySQL): Database connections should always remain strictly internal.
Using our tool, you can simulate an external connection attempt to ensure your firewall (such as iptables, UFW, or cloud security groups) is correctly configured to block unauthorized access from the outside world.