A check box lets you activate logging. If activated, linuxconf will add a line to /var/log/htmlaccess.log each time there is an http request.
The rest of the dialog goes like this. You must specify pairs. You specify a host or a network and optionally a netmask. Your options in specifying a host or network are
A default netmask is computed based on the type of the first entry (Is it a host or network). You can override this by supplying the optional netmask. Also, it is possible to specify a host name with a wider netmask, allowing access by all hosts on this host's network.
Some examples:
machine1.foo.com
(empty netmask imply 255.255.255.255)
10.1.2.0
255.255.255.0
eth0
(empty netmask grab the current one for eth0)
The first pair allows one machine. The second and third allow complete networks.