1. IP Subnet Calculator for X. The IP Subnet Calculator is a tool that allows network administrators to make calculations that will assist in subnetting a network. You give the network class and subnet bits and you get back the maximum number of subnets, maximum number of hosts per subnet, a bimap showing the breakdown of network bits, subnet bits, and host bits, the decimal and hexadecimal class netmask, the decimal and hexadecimal subnet mask and lists subnets and host information. CIDR support, reverse engineer the network information for a particular interface (e.g. eth0, ppp0) and save capability. From Debian 3.0r0 APT