IPCALC(1)                  OpenBSD Reference Manual                  IPCALC(1)

NAME
     ipcalc - calculate IPv4 network sizes, masks and broadcasts

SYNOPSIS
     ipcalc address / netmask
     ipcalc -s mask1,mask2,...  [-v] address / netmask
     ipcalc -r [-v] address : address
     ipcalc -n netmask

DESCRIPTION
     ipcalc is a small tool that operates on IPv4 networks.  It can operate in
     one of four modes: network describing, netmask describing, finding or
     splitting.  When called without any flags, ipcalc operates in network de-
     scribing mode.  Options are exclusive except for -v and are as follows:

     -s      Enable network splitting, the argument is a list of integers sep-
             arated by commas.  Each integer represents a number of IPs.  For
             each integer, ipcalc will try to find a network that is a sub
             network of the main network and that can contain the number of
             IPs specified.

     -r      Enable network finding. Ipcalc will find as few networks as pos-
             sible between the two addresses specified.

     -n      Netmask describing. Ipcalc will print the netmask in all formats
             it knows.

     -v      Operates only on network finding and splitting in which case it
             prints detailed information for each network.

NETMASKS
     Netmasks can be specified in one of three ways:

     prefix length
             An integer between 1 and 32 inclusive which indicates the numbers
             of bits set in the address.

     quad-dotted address
             A traditionnal IPv4 address such as 255.255.255.0

     hex notation address
             An address in hex notation such as 0xffffff00

OpenBSD 4.0                    October 19, 2006                              1