# No accept Ipv6 in IPAddr

**URL:** <https://www.ruby-forum.com/t/no-accept-ipv6-in-ipaddr/104063>\
**Category:** Ruby\
**Created:** [May 13, 2007, 9:42pm UTC](https://www.ruby-forum.com/t/no-accept-ipv6-in-ipaddr/104063 "2007-05-13T21:42:19Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![shingara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8491ac/32.png) [@shingara](https://www.ruby-forum.com/u/shingara)\
**Post date:** [May 13, 2007, 9:42pm UTC](https://www.ruby-forum.com/t/no-accept-ipv6-in-ipaddr/104063/1 "2007-05-13T21:42:19Z")

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Hi,

I ask me a question since few day and I don’t understand why this code  
doesn’t run :

require ‘ipaddr’  
IPAddr.new ‘2002:0000:1234:4561’

In fact this code raise an Exception :

/usr/lib64/ruby/1.8/ipaddr.rb:422:in `initialize’: invalid address  
(ArgumentError)

But this adress is syntactically valid like an Ipv6. My search lead me  
to this conclusion :

IPAddr think my IP like an invalid adress because it hadn’t a name  
resolution. The line who raise the exception is :

IPSocket.getaddress(prefix)

For me, the prefix is ‘2002:0000:1234:4561’, because it’s never modify  
before in intialize of IPAddr (Verify with the debuggeur). The command  
follow prouve it :

hello% host 2002:0000:1234:4561  
Host 2002:0000:1234:4561 not found: 3(NXDOMAIN)

or with irb :

hello% irb  
irb(main):001:0\> require ‘socket’  
=\> true  
irb(main):002:0\> IPSocket.getaddress(‘2002:0000:1234:4561’)  
SocketError: getaddrinfo: Name or service not known  
from (irb):2:in `getaddress’  
from (irb):2

But , it’s not specify anywhere that an IPAddr must be “valid” for be  
use. Likewise, if we see the code of this file ipaddr.rb, We remark  
that in first step, there are :

unless Socket.const\_defined? “AF\_INET6”

But if you have compile Ruby with Ipv6 support like some binary linux  
distribution, this variable is define. So the  
override of the method getaddress made after this unless is never  
execute. In this new method, we can see that :

return true if /\A[\dA-Fa-f]{1,4}(:[\dA-Fa-f]{1,4})\*\Z/ =~ addr

With this my Ipv6 is valid.

The question that I ask me is the follow :

It’s a bug or not ?

thank for your answer

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<div class="post-metadata">

**Author:** ![shingara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8491ac/32.png) [@shingara](https://www.ruby-forum.com/u/shingara)\
**Post date:** [May 13, 2007, 10:11pm UTC](https://www.ruby-forum.com/t/no-accept-ipv6-in-ipaddr/104063/2 "2007-05-13T22:11:22Z")

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On Mon, May 14, 2007 at 04:41:13AM +0900, Cyril M. wrote:

> I ask me a question since few day and I don’t understand why this code  
> doesn’t run :
> 
> require ‘ipaddr’  
> IPAddr.new ‘2002:0000:1234:4561’
> 
> In fact this code raise an Exception :
> 
> /usr/lib64/ruby/1.8/ipaddr.rb:422:in `initialize’: invalid address  
> (ArgumentError)

Correct - that’s not a valid IPv6 address. IPv6 addresses have 128 bits;  
your address has only 64 bits.

irb(main):001:0\> require ‘ipaddr’  
=\> true  
irb(main):002:0\> IPAddr.new ‘2002:0000:1234:4561’  
ArgumentError: invalid address  
from /usr/lib/ruby/1.8/ipaddr.rb:423:in `initialize' from (irb):2 irb(main):003:0> IPAddr.new '2002:0000:1234:4561/64' ArgumentError: invalid address from /usr/lib/ruby/1.8/ipaddr.rb:423:in`initialize’  
from (irb):3  
irb(main):004:0\> IPAddr.new ‘2002:0000:1234:4561::0/64’  
=\> #\<IPAddr:  
IPv6:2002:0000:1234:4561:0000:0000:0000:0000/ffff:ffff:ffff:ffff:0000:0000:0000:0000\>

The “::” means “add as many :0000:'s as necessary to make up to 128  
bits”.  
But you could also use a valid 128 bit address explicitly:

irb(main):005:0\> IPAddr.new ‘2002:0000:1234:4561:0000:0000:0000:0000’  
=\> #\<IPAddr:  
IPv6:2002:0000:1234:4561:0000:0000:0000:0000/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff\>

> Host 2002:0000:1234:4561 not found: 3(NXDOMAIN)  
> If you give an address which is not syntactially valid as an IPv6  
> numeric  
> address, I guess it’s reasonable for Ruby to try it as a hostname  
> instead.

Brian.

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<div class="post-metadata">

**Author:** ![shingara](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/8491ac/32.png) [@shingara](https://www.ruby-forum.com/u/shingara)\
**Post date:** [May 14, 2007, 12:20am UTC](https://www.ruby-forum.com/t/no-accept-ipv6-in-ipaddr/104063/3 "2007-05-14T00:20:35Z")

</div>

On 5/13/07, Brian C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > (ArgumentError)  
> > irb(main):003:0\> IPAddr.new ‘2002:0000:1234:4561/64’  
> > =\> #\<IPAddr: IPv6:2002:0000:1234:4561:0000:0000:0000:0000/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff\>  
> > hello% host 2002:0000:1234:4561  
> > Host 2002:0000:1234:4561 not found: 3(NXDOMAIN)
> 
> If you give an address which is not syntactially valid as an IPv6 numeric  
> address, I guess it’s reasonable for Ruby to try it as a hostname instead.

Ok, thanks for your answer. I don’t know enough the specification of  
Ipv6. I thought that this adress was valid.