Port scanner, a free online tool allows you to scan commonly used ports on your computer. Scan takes less than a minute, after which the result will be displayed in a table. if you are connected to Internet, unnecessary opened ports can prove as a security threat.

2. Open ports detection In order to determine if a TCP port is open, Nmap takes advantage of the Three way handshake mechanism used by TCP to establish a connection between a client and a server. There are two main methods for detecting open TCP ports: Connect-Scan (Nmap -sT) The recommended scan type is "connect()", however other scan types can also be useful depending on the network of the target host, a "SYN Stealth" scan type can also prove to be useful when there's a firewall blocking the ports. The open port checker is a tool you can use to check your external IP address and detect open ports on your connection. This tool is useful for finding out if your port forwarding is setup correctly or if your server applications are being blocked by a firewall. To test if you might be vulnerable to the SASSER virus, use the above port scan tool to scan port 445. If the portscan says it can get through port 445 on whatever firewall you hopefully have, and your computer's port 445 is also open/active, then you may be susceptible to the SASSER virus.

Calendar Server [CalDAV SSL] 8443. Queued

To test if you might be vulnerable to the SASSER virus, use the above port scan tool to scan port 445. If the portscan says it can get through port 445 on whatever firewall you hopefully have, and your computer's port 445 is also open/active, then you may be susceptible to the SASSER virus.

The recommended scan type is "connect()", however other scan types can also be useful depending on the network of the target host, a "SYN Stealth" scan type can also prove to be useful when there's a firewall blocking the ports.

IPv6 Online Port Scanner IPv6Scanner is a port scanner that allows you to probe a server for open, closed or filtered ports. You can specify a host name, IPv4 or IPv6 address.