Sometimes to test in a closed off environment the local loopback address is needed to be used to test the 4D Web Server.
With IPv6 out, there are two addresses that the machine may use for it's local loopback address.
The IPv4 is 127.0.0.1 and the IPv6 is ::1.
When selecting the IP in 4D the address displayed in the list of choices is the IPv6 if available and IPv4 if not.
Both of these addresses can be connect to by connecting to localhost such as
127.0.0.1 can be connected as is
To connect to ::1 the url must be formatted as [::1]