The TCP tool will “ping” an IP address at a specific TCP port and report if the host accepts the connection. The syntax is IPAddress:PortNumber (e.g. 18.104.22.168:80) Great use for this tool is to test if your servers are open on specific ports. You can also setup a monitor on a TCP port to tell you when your critical services (e.g. POP, LDAP, IMAP) are down.