Open port check

Why might an open port be a concern?

An open port means that a service may accept incoming connections. Personal computers commonly use firewalls to block unsolicited connections, while public servers need open ports to provide services such as HTTP and HTTPS. When you use a VPN, open ports on its public IP address may belong to services running on the VPN server.

Why should I check for open ports?

Unexpected open ports are worth investigating so you know which services are exposed. An open port may also reveal information about the server or service using the IP address. An open port alone does not prove that your device is insecure or that you are using a VPN or proxy.

What ports are included in the test?

The test checks the following commonly used ports.

• 21 FTP (File Transport Protocol command channel)
• 22 SSH (Secure Shell protocol and Secure file transfers)
• 23 Telnet (Unencrypted application protocol)
• 25 SMTP (Simple mail transfer protocol used by mail servers)
• 53 DNS (Domain Name System protocol used by public resolvers)
• 80 HTTP (Hypertext transfer protocol used by public web-servers)
• 443 HTTPS / SSTP (Hypertext Transfer Protocol Secure / SSTP VPN protocol)
• 445 SMB (SMB file sharing protocol)
• 465 SMTPS (Simple Mail Transfer Protocol over SSL)
• 995 POP3S (Post Office Protocol 3 over SSL)
• 1194 OpenVPN (OpenVPN protocol)
• 1723 PPTP (PPTP tunneling VPN protocol)
• 3306 MYSQL (MYSQL database protocol)
• 3389 RDP (Remote Desktop Protocol)
• 5555 SoftEther (SoftEther VPN server protocol)