NAME

       subnetcalc — IPv4/IPv6 Subnet Calculator

SYNOPSIS

       subnetcalc [Address] [Netmask/Prefix] [-n] [-uniquelocal] [-uniquelocalhq]

DESCRIPTION

       subnetcalc  is  an  IPv4/IPv6  subnet  address  calculator. For given IPv4 or IPv6 address and netmask or
       prefix length, it calculates network address, broadcast address, maximum number of hosts and host address
       range. Also, it prints the addresses in binary  format  for  better  understandability.  Furthermore,  it
       prints useful information on specific address types (e.g. type, scope, interface ID, etc.).

ARGUMENTS

       The following arguments have to be provided:

       Address
               The  IP  address.  If  a  hostname  is provided here, it is tried to resolve the address by a DNS
               server and the  first  returned  address  is  used.  Internationalized  Domain  Names  (IDN)  are
               supported.

       Netmask/Prefix
               The netmask or prefix length (0-32 for IPv4; 0-128 for IPv6).

       -n      Skip trying a reverse DNS lookup.

       -uniquelocal
               Given  an  IPv6  address, the first 48 bits of the address are replaced by a randomly chosen IPv6
               Unique Local prefix in fc00::/7 (see also RFC 4193). Under Linux, /dev/urandom is used for random
               number generation.

       -uniquelocalhq
               Like -uniquelocal, but using /dev/random instead on  Linux  systems  for  highest-quality  random
               number  generation.  On  other  systems, this option is equal to -uniquelocal. Note, that reading
               from /dev/random may take some time. You can speed up this process  by  delivering  random  input
               e.g. by pressing keys or moving the mouse.

EXAMPLES

       subnetcalc 132.252.250.0 255.255.255.0

       subnetcalc 132.252.250.0/255.255.255.0

       subnetcalc 132.252.250.0 24

       subnetcalc 132.252.250.0/24

       subnetcalc fec0:2345:6789:1111:221:6aff:fe0b:2674 56

       subnetcalc 2a00:1450:8007::69 64

       subnetcalc ff08::1:2:3

       subnetcalc 131.220.6.5/24

       subnetcalc 132.252.181.87 -n

       subnetcalc www.iem.uni-due.de 24

       subnetcalc www.six.heise.de

       subnetcalc fd00:: 64 -uniquelocal

       subnetcalc fd00::9876:256:7bff:fe1b:3255 56 -uniquelocalhq

       subnetcalc düsseldorf.de 28

       subnetcalc www.köln.de

       subnetcalc räksmörgås.josefsson.org 24

AUTHORS

       Thomas Dreibholz
       http://www.iem.uni-due.de/~dreibh/subnetcalc
       mailto://dreibh@iem.uni-due.de

subnetcalc                                        June 19, 2010                                    subnetcalc(8)