www.RT.com bad dns record

Fri Jul 8 09:11:59 UTC 2016

On 2016-07-08 04:33, Matt Palmer wrote:
> On Thu, Jul 07, 2016 at 06:36:23PM -0700, Ca By wrote:
>> On Thursday, July 7, 2016, Spencer Ryan <sryan at arbor.net> wrote:
>>
>>> Dotted-quad notation is completely valid, and works fine.
>>>
>>> https://en.wikipedia.org/wiki/IPv6_address#Presentation
>>>
>>> http://[::ffff:37.48.108.112] loads fine in my browsers.
>> It may be legit on your network, but people generally don't do that.... If
>> they publish a aaaa record, it usually has a legit v6 address in it.
> That is a legit IPv6 address.

No it is not. It is a format intended to be used only within a process 
to store IPv4 addresses in a single common data structure for IPv4/IPv6 
or for use in a socket API so a combined IPv4/IPv6 interface can be 
provided. There is no requirement that other processes understand it. 
There is no requirement that IPv4-mapped addressing is not disabled on a 
system supporting IPv6 (RFC4291 section 8 security considerations).

 From RFC5156:

      2.2 <https://tools.ietf.org/html/rfc5156#section-2.2>. IPv4-Mapped
      Addresses

    ::FFFF:0:0/96 are the IPv4-mapped addresses [RFC4291 <https://tools.ietf.org/html/rfc4291>].  Addresses
    within this block should not appear on the public Internet.

You can put it in a AAAA record just as you can configure a 10.0.0.0/8 
address there, but there can be no expectation that it will do anything 
useful outside your own environment.

Regards,

Baldur