Advanced network calculator and address planning helper.
NetCalc is a tool made by network admins, for network admins. It supports adding (aggregating) networks, subtracting a network from a larger network, doing addition and subtraction of multiple networks at once, and more functionality is to come in future releases.
NetCalc supports both IPv4 and IPv6, and works very efficiently even with very large networks. It uses the excellent netaddr library for the core address manipulation.
This program requires either Python 3 (recommended) or Python 2.
Contents
Using NetCalc is quite simple. All functionality is split into commands, each of which receive their own set of specific arguments.
Add networks, aggregating as much as possible.
$ netcalc add 198.18.0.0/24 198.18.1.0/24 10.1/16 10/16 10.0.0.0/15 198.18.0.0/23
This command can be very useful e.g. for calculating a minimal set of prefixes to announce with BGP.
Another real-life example would be comparing the routing tables from two separate routers (each with prefixes broken up in different ways), to see if they are equivalent (both cover the same networks). If the aggregate from one router matches the aggregate from the other, then they are indeed equivalent.
Add networks from a file, aggregating as much as possible.
This is a variant of the add command above, which reads the networks from a
file (one per line). For example, given the following file:
- networks.txt
198.18.0.0/24 198.18.1.0/24 10.1/16 10/16
These networks could be added like so:
$ netcalc add-file networks.txt 10.0.0.0/15 198.18.0.0/23
Subtract a network from another, splitting as necessary.
$ netcalc sub 192.0.2.0/24 192.0.2.0/28 192.0.2.16/28 192.0.2.32/27 192.0.2.64/26 192.0.2.128/25
Split a network into subnets of a certain length.
$ netcalc split 198.18.64.0/18 20 198.18.64.0/20 198.18.80.0/20 198.18.96.0/20 198.18.112.0/20
It is also possible to do a hierarchical split, showing all the steps from a certain length to a specified maximum length:
$ netcalc split 198.18.64.0/18 19 21
198.18.64.0/19
198.18.64.0/20
198.18.64.0/21
198.18.72.0/21
198.18.80.0/20
198.18.80.0/21
198.18.88.0/21
198.18.96.0/19
198.18.96.0/20
198.18.96.0/21
198.18.104.0/21
198.18.112.0/20
198.18.112.0/21
198.18.120.0/21
Add and subtract networks using an arbitrarily long mathematical expression.
$ netcalc expr 2001:db8::/34 - 2001:db8::/38 + 2001:db8:100::/41 2001:db8:100::/41 2001:db8:400::/38 2001:db8:800::/37 2001:db8:1000::/36 2001:db8:2000::/35
Provide static information about a network. Shows the network address, netmask, first and last addresses, and so on.
$ netcalc info 2001:db8::8000:0:0:a:5/56 Compact address - 2001:db8:0:8000::a:5 Expanded address - 2001:0db8:0000:8000:0000:0000:000a:0005 Address type - Global Unicast Network address - 2001:db8:0:8000::/56 Network mask - ffff:ffff:ffff:ff00:0:0:0:0 Prefix length - 56 Host wildcard - 0:0:0:ff:ffff:ffff:ffff:ffff Broadcast address - N/A Address count - 4722366482869645213696 First address - 2001:0db8:0000:8000:0000:0000:0000:0000 Last address - 2001:0db8:0000:80ff:ffff:ffff:ffff:ffff
It is possible to expand command-line arguments from a text file, for any
command, by referencing the filename with a @ placeholder. The file's
contents will be read and inserted as though they had been typed at the
command-line. Each line of text will turn into a separate command line
argument.
Argument expansion is useful for commands which don't already support receiving
a filename from which to read their arguments. Using this, it is possible for
example to calculate an arbitrarily long expression with the expr command.
For example, given the following file:
- /tmp/math-arguments.txt
2001:db8::/34 - 2001:db8::/38 + 2001:db8:100::/41
This expression could be calculated like so:
$ netcalc expr @/tmp/math-arguments.txt 2001:db8:100::/41 2001:db8:400::/38 2001:db8:800::/37 2001:db8:1000::/36 2001:db8:2000::/35
It is even possible (albeit perhaps farfetched) to specify the actual command within the argument file:
- /tmp/arguments.txt
sub 10.0.0.0/24 10.0.0.64/27
Which would yield:
$ netcalc @arguments.txt 10.0.0.0/26 10.0.0.96/27 10.0.0.128/25
Of course, it would also be possible to use argument expansion to read networks
from a file as arguments into the add command. However, this would be rather
redundant, as it is equivalent to just using the add-file command,
exemplified above.
Given the file:
- networks.txt
198.18.0.0/24 198.18.1.0/24 10.1/16 10/16
These networks could be added like so:
$ netcalc add @networks.txt 10.0.0.0/15 198.18.0.0/23
The easiest, portable, way to install NetCalc is through the official Python Package Index, using a package manager such as pip:
$ sudo pip install netcalc
This will install NetCalc globally, and take care of installing all necessary dependencies first.
It is also possible to install only to the local user's environment, without changing the global system:
$ pip install --user netcalc
This will install NetCalc in the user's environment, which can be e.g. in
~/.local in GNU/Linux, UNIX and Mac OSX, or %APPDATA%\Python in
Windows. You will need to run netcalc from within the user environment: on
GNU/Linux for example, this will be ~/.local/bin/netcalc.
There are packages available for Debian Jessie (.deb), which should also work for Ubuntu Linux:
- python-netcalc (for Python 2)
- python3-netcalc (for Python 3)
A package for Gentoo Linux (ebuild) is also planned for future releases.
NetCalc can also be run directly from the source directory, as long as the requirements are already installed.
The only requirement is netaddr. On a Debian or Ubuntu system, install the
python3-netaddr package (for Python 3), or python-netaddr (for Python
2). On a Gentoo system, install dev-python/netaddr.
To run from source, just execute ./netcalc.py from within the root of the
source directory:
$ cd netcalc $ ./netcalc.py add 10.0.0.24/29 10.0.0.16/29 10.0.0.16/28
Future plans for NetCalc include, in no particular order:
- new command for static information (netmask/bitmask, IP range)
- new command for WHOIS queries
- make expr command more generic, allow e.g. splitting subnets
- ability to read networks from file in different formats (CSV, etc.)
- create packages for common GNU/Linux distributions, and installer for Windows
- ???
Suggestions are quite welcome :)
NetCalc is developed by Israel G. Lugo <israel.lugo@lugosys.com>. Main repository for cloning, submitting issues and/or forking is at https://github.com/israel-lugo/netcalc
Copyright (C) 2016, 2017 Israel G. Lugo <israel.lugo@lugosys.com>
NetCalc is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
NetCalc is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with NetCalc. If not, see <http://www.gnu.org/licenses/>.