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
subnetcalc ç´è±.w3.mag.keio.ac.jp 29
AUTHORS
Thomas Dreibholz
http://www.iem.uni-due.de/~dreibh/subnetcalc
mailto://dreibh@iem.uni-due.de