Provided by: ripcalc_0.2.7-1_amd64 
NAME
ripcalc - a tool for network addresses
SYNOPSIS
ripcalc 127.0.0.1
ripcalc -4/--ipv4 127.0.0.1
ripcalc -6/--ipv6 ::1
ripcalc -f/--format “%a/%c” 127.0.0.1
ripcalc -m/--mask 28 127.0.0.1
ripcalc -c/--csv path/to/csv [-i/--field network] 127.0.0.1
ripcalc -l/--list 127.0.0.1
ripcalc -a/--available
ripcalc -s/--file [-] 127.0.0.1
ripcalc -e/--encapsulating [-s/--file name] [--group CIDR]
ripcalc -s/--file name [--inside/--outside] 127.0.0.1
ripcalc -b/--base [8, 10, 16 etc]
ripcalc -d/--divide [CIDR] 127.0.0.1/24
ripcalc –networks [CIDR] 127.0.0.1/24
ripcalc -q/--quiet
ripcalc -h/--help
DESCRIPTION
ripcalc can read IPv4/IPv6 addresses from command line or standard input and output different formats or
associated networks from CSV.
ripcalc can format network addresses, find matches in CSV or process a list.
ripcalc can convert input addresses that are in other number formats such as hex or octal.
Given a list of IP addresses, print only those that match the network. When s and inside are used, only
addresses from -s are printed if they are that are inside of the input IP network from the command line.
This can be reversed with --outside, (e.g. ripcalc -s - --inside 192.168.0.0/16).
When -a is used, addresses read from -s will not be shown when listing -l a network, showing only avail‐
able addresses.
When --reverse is used the inputs, sources or both can be treated as back-to-front.
ripcalc can return a list of subnets when a network is provided along with the --divide argument and a
subnet CIDR mask.
When --encapsulating is used the containing network will be returned, use with --group to limit the range
that an encapsulating network can grow.
The number (%D) of subnets can be printed when using the --group argument with the %N formatters. The
argument should be the CIDR mask, see below for example.
If base is a negative number, input addresses are treated as though the input is a signed integer in
base.
If --quiet is specified then parsing error messages will be suppressed.
CSV
Network matches can be returned from a CSV.
$ cat nets.csv
network,range,owner
rfc1918,192.168.0.0/16,bob
rfc1918,172.16.0.0/12,cliff
rfc1918,10.0.0.0/8,mr nobody
$ ripcalc --csv nets.csv -i range --format '%{owner}\n' 192.168.0.0
bob
Addresses can be read via file or from stdin (-):
$ cat list
127.0.0.1/28
10.0.0.1/28
192.168.1.1/30
172.18.1.1/30
10.0.0.0/30
$ ripcalc --csv nets.csv -i range --format '%{range} %{owner}\n' -s list
10.0.0.0/8 mr nobody
192.168.0.0/16 bob
172.16.0.0/12 cliff
10.0.0.0/8 mr nobody
FORMAT
% denotes a format control character, followed by one of the following:
placeholder effect
───────────────────────────────────────
%a IP address string
%n Network address string
%s Subnet address string
%w Wildcard address string
%b Broadcast address string
Additional characters prefixing the above placeholder can control the representation:
placeholder effect
────────────────────────────────────────────────────
%B Binary address string
%S Split binary at network boundary
string
%l Unsigned integer string
%L Signed integer string
%x Hex address string
Other format characters:
placeholder effect
────────────────────────────────────────────────────
%c CIDR mask
%C In encapsulated context, used address
count
%t Network size
%r Network reservation information (if
available)
%d Matching device interface by IP
%m Matching media link interface by net‐
work
%p PTR record
%k RBL/reverse DNS-style format
%D Network size (--networks)
%N Number of subnets (--networks)
%% %
\n Line break
\t Tab character
%xa gives the address in hex, or %Sa to return the binary address, split at the network boundary.
When using CSV fields can be matched by name when network matched:
--format '%{name}'
inside/outside
When --inside or --outside are given addresses that match --file are printed. If no matches are found
ripcalc will exit non-zero.
subnets
For large networks it can be useful to see the number of subnets, to see the number of /29 subnets within
a /24 network, the command would look like this:
ripcalc --networks 29 192.168.230.0/24
IP is: 192.168.230.0/24
Broadcast is: 192.168.230.255
Network is: 192.168.230.0
Subnet is: 255.255.255.0
Wildcard is: 0.0.0.255
Networks (29): 32
Or for a IPv6 /48 network that you want to subnet into /64, you can see there are 65536 subnets:
ripcalc --networks 64 2001:db8:1::/48
IP is: 2001:db8:1::/48
Expanded: 2001:0db8:0001:0000:0000:0000:0000:0000
Network is: 2001:0db8:0001:0000:0000:0000:0000:0000
Last host address: 2001:0db8:0001:ffff:ffff:ffff:ffff:ffff
Subnet is: ffff:ffff:ffff:0000:0000:0000:0000:0000
Networks (64): 65536
encapsulating
Suppose a large flood of requests are from a network pattern, to preserve service you may want to block
the whole network that encapsulates a list:
please ip route add blackhole `ripcalc -e 192.168.56.10 192.168.57.1 192.168.44.47`
Networks can be grouped, in a scenario where you have a list of unwanted traffic, you can turn this into
a list of small networks to block, supposing you don’t want to block anything that covers more than a
/19:
cat bad_traffic | ripcalc --encapsulating --group 19 --format cidr
When using group the unique IP address count is available in the %C format string. This can give an
overview of which networks have most IP sources:
cat bad_traffic | ripcalc --encapsulating --group 19 --format '%C %a/%c\n' | sort -rn
AUTHORS
Ed Neville (ed-ripcalc@s5h.net).
ripcalc 0.2.7 08 August 2025 ripcalc(1)