When you run HostName Commander, it displays the current host name information for your computer as a tree-like structure:

(Note that if you are running HostName Commander for the fist time, and you have not previously set up any host names, you could see a blank window, or a window with just one IP address, 127.0.0.1, with only one host name "localhost" mapped to it.)

The main window of HostName Commander displays the list of the IP addresses, with the lists of the name hosts mapped to each IP address. To map a host name to an IP address, you would use the Add Host Name command to add a host name to one of the IP addresses displayed in the window. After a host name has been added, you could activate or deactivate it, by clicking on the checkbox next to the host name with the mouse. When you activate a host name, you make it resolve to the IP address it is attached to, and all network requests to that host name would be directed to the computer with that IP address. When you deactivate a host name (by clearing the check box next to it), you break the relationship between the host name and the IP address, and that makes the host name to resolve as usual, as if HostName Commander were not present in your computer at all.

HostName Commander lets you create several groups of host names mapped to the same IP address, to make it easier to manage such groups independently on each other. You can enter short comments for both the IP address and the host names, which are displayed in the parenthesizes next to the IP addresses and host names. You can move the host names between the IP addresses with the mouse or using the Move Up/Down commands.