From: Eric Hodel <drbrain@...7.net>
Date: 2011-11-01T05:08:39+09:00
Subject: Re: UDPSocket#bind(ip, port) fails under IPv6 !

On Oct 31, 2011, at 7:16 AM, Iņaki Baz Castillo wrote:
> s4 = UDPSocket.new
>  s4.bind IPv6, PORT
>  puts "=> OK"
> rescue => e
>  $stderr.puts "#{e.class}: #{e}"
> end
> 
> 4) binding in IPv6 UDP...
> Errno::EAFNOSUPPORT: Address family not supported by protocol - bind(2)
> ----------------------
> 
> Is it a known issue? If not I will report it.


You need to create an AF_INET6 UDPSocket to bind an IPv6 address

  $ ruby -vr 'socket' -e 'u = UDPSocket.new Socket::AF_INET6; u.bind "::1", 9999'
  ruby 1.8.7 (2010-01-10 patchlevel 249) [universal-darwin11.0]

Repeated from http://redmine.ruby-lang.org/issues/5525