Originally Posted by Fou-Lu
If I understand your question properly, that is what CIDR could be used for.
You give a CIDR an IP and a subnetmask or CIDR netmask/mask bits, then you ask it if a provided IP is considered valid within that block. This works perfectly for office domains.
I believe CIDR is directly implemented into Apache as well, so you can also use allow/deny overrides and CIDR notation.
Sure, will work on post my updates here....