Subnet calculation and discovery utility for BSD & Linux.
The subcalc utility is used for subnet calculation and IPv6 DNS PTR record generation. subcalc takes command line arguments in a similar format to ifconfig(8) so the synopsis should be familiar to the user. Given an address family, address and a netmask/prefix length, subcalc will calculate the number of hosts and address ranges of the specific network. Specifying the ``print'' option to to the end of the command line will result in every single network address for the specified net- work being printed to stdout.
subcalc was designed for network engineers which setup fine grained firewalls, packet filters, access control lists and network subdivisions for both IP and IPv6 servers and networks.
usage: subcalc [inet | inet6] address [netmask | mask ] mask <print>
subcalc [inet | inet6] address [prefixlen] len <print>
subcalc [inet | inet6] hosts value
subcalc [int6 | arpa6] address hostname
subcalc stf [inet | inet6 ] address
To calculate the network range, number of hosts, prefixlen or CIDR and netmask for the 10.0.0.1/24 (255.255.255.0) network.
% subcalc inet 10.0.0.1/24
Anyone of the following will achieve the exact same thing:
% subcalc inet 10.0.0.1 netmask 255.255.255.0
% subcalc inet 10.0.0.1 netmask 0xffffff00
% subcalc inet 10.0.0.1 prefixlen 24
To generate a list of nodes for the specified network one could use anyone of the following methods:
% subcalc inet 10.0.0.1/24 print
% subcalc inet 10.0.0.1 netmask 255.255.255.0 print
% subcalc inet 10.0.0.1 netmask 0xffffff00 print
% subcalc inet 10.0.0.1 prefixlen 24 print
Arbitrarily, the same thing can be done for IPv6. To calculate the network range, number of hosts, prefixlen etc for the 3ffe:beef:13e1:4c92::cd90/48 network, one could use any of the following:
% subcalc inet6 3ffe:beef:13e1:4c92::cd90/48
% subcalc inet6 3ffe:beef:13e1:4c92::cd90 netmask ffff:ffff:ffff::
% subcalc inet6 3ffe:beef:13e1:4c92::cd90 prefixlen 48
Copyright (c) Christian S.J. Peron (csjp@sqrt.ca)
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