Open port check

Why an open port is suspicious?

The open port – is not a common PC config. Both Windows and Linux firewall the incoming connections to get rid of security risks. Usually only the public servers have opened ports to handle incoming connections. So if you are using VPN there is a big chance to have opened ports on your IP: 1194 (OpenVPN), 1793 (PPTP), 443 (HTTPS), 80 (HTTP). The most secure VPN has to behave like a common client PC and close down these ports (i.e. use different IPs for incoming and outgoing connections or use UDP protocol only etc.).

Why should I take it into consideration?

As mentioned above the open port is a security issue and you should really know what you are doing if the port is opened. Secondly the open port flags your IP as VPN or Proxy (i.e. it is visible to anyone that you are trying to hide your real IP). Will you trust the user who are trying to hide the real IP?

What ports are included in the test?

The test tries to open the most common 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)