From: Tanaka Akira <akr@...>
Date: 2011-11-01T20:39:41+09:00
Subject: [ruby-core:40620] Re: [ruby-trunk - Bug #5525] UDPSocket#bind(ip, port) fails under IPv6 => Errno::EAFNOSUPPORT

2011/11/1 I�aki Baz Castillo <ibc@aliax.net>:
>
> Thanks a lot. But why is it required just for UDP? In TCP I can use "TCPServer.new some_ipv6, port" with no problem. Why UDPSocket requires special handling for IPv6?

The protocol (IPv4/IPv6) is determined at socket creation.

The argument of TCPServer.new(ipv6_address) makes Ruby to find that
the protocol is IPv6.
So TCPServer.new creates a socket for IPv6.

But Ruby cannot find the protocol for UDPSocket.new without arguments.
In that case, UDPScoket.new creates a socket for IPv4.
You meet an error when you use it for IPv6.
-- 
Tanaka Akira