IPAddr provides a set of methods to manipulate an IP address. Both IPv4 and IPv6 are supported.

Build Status


This library is part of the standard ruby distribution as default gem and synchronized periodically, but you can explicitly depend on this gem with version constraints as necessary, like when you need a newer version than comes with older versions of ruby.

For example, you can add this line to your application's Gemfile:

gem 'ipaddr', '~> 1.2'

And then execute:

$ bundle

Or install it yourself as:

$ gem install ipaddr


require 'ipaddr'

ipaddr1 = IPAddr.new "3ffe:505:2::1"

p ipaddr1                   #=> #<IPAddr: IPv6:3ffe:0505:0002:0000:0000:0000:0000:0001/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff>

p ipaddr1.to_s              #=> "3ffe:505:2::1"

ipaddr2 = ipaddr1.mask(48)  #=> #<IPAddr: IPv6:3ffe:0505:0002:0000:0000:0000:0000:0000/ffff:ffff:ffff:0000:0000:0000:0000:0000>

p ipaddr2.to_s              #=> "3ffe:505:2::"

ipaddr3 = IPAddr.new ""

p ipaddr3                   #=> #<IPAddr: IPv4:>


The ipaddress gem is a popular, extensive library for manipulating IP addresses with a layer of compatibility with ipaddr. If you need a richer set of features than ipaddr has, try this library instead.


After checking out the repo, run bundle install to install dependencies. Then, run rake test to run the tests.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.


Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/ipaddr.


The gem is available as open source under the terms of the 2-Clause BSD License.