[dns-operations] IPv6 Connectivity on Firefox

Mathieu Goessens gebura at poolp.org
Thu Nov 26 10:44:03 UTC 2015


Le 2015-11-25 11:06, Fatemah Alharbi a écrit :
> Hello,
> I am a PhD student at UC Riverside, CA, USA. I am conducting
> experiments using Firefox to test Ipv6 connectivity and I would
> appreciate your cooperation and help to answer the following
> questions.
> By default, Firefox has Ipv6 enabled. When I visit a particular
> website, Firefox always sends 2 DNS queries: A query(For IPv4 
> address)
> and AAAA query (for IPv6 address). It always prefers the IPv4 
> address,
> why?
> Please see the attached file: block_A_record_google.pcapng. I blocked
> the IPv4 response packets (for the A queries) of the domain name
> clients1.google.com to see how Firefox would behave if it gets only
> the AAAA response. Even if Firefox gets a positive response for the
> AAAA query, it ignores the response and keeps asking for the Ipv4
> address! Why?
> Does that have anything to do with my ISP Ipv6 connectivity? My ISP,
> Charter, doesn’t support Ipv6 connectivity to residential customers
> yet. If so, how Firefox does know that my ISP doesn’t support Ipv6
> connectivity? How does Firefox know that the host triggering the DNS
> requests is not within an Ipv6 network?
> This is the result of the Ipv6 connectivity test on Firefox (Please
> see the attached file: Test Your Ipv6 Connectivity-Firefox.pdf):
> Thank you for your time. I look forward to hearing from you soon.

As mentionned by Shane, better to ask directly the firefox network


Also, better to specify  what's your test environnement (ffx version,
OS as it is likely to be OS specific etc)

Mathieu Goessens
IT consultant.
gebura at poolp.org
+ 33 6 07 91 54 87

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