ip "127.0.0.1"
This key defines the IP address that the engine is listening. If this value is not configured and no IP address is specified on the command line then the engine will listen on all IP addresses that the machine is configured to serve. Using this key a single IP address can be configured.
The IP number should be defined as a string in the form of x.x.x.x
For example defining this key to be "127.0.0.1" will mean that the server will only be available from the local machine. This can be a safe installation mode for BASIC web programs that run on a single machine most probably from a CD installed program and serve only the person sitting in front of the PC.