IPv6 connectivity to 1.gravatar.com and s1.wp.com, amongst others, is broken

  • Unknown's avatar
    csamuel · Member ·

    Hi folks,

    I can’t see a better way of reporting this, so trying here..

    I’ve noticed that Gravatars were not working recently, but only just bothered to try and find out what, and it seems to be that the host for gravatars, 1.gravatar.com, is now unreachable via IPv6 despite having an IPv6 address in DNS.

    It looks like an upstream problem at your CDN, EdgeCast.

    This is also affecting IPv6 enabled wp.com sites like s1.wp.com.

    Best of luck!
    Chris

    The blog I need help with is: (visible only to logged in users)

  • Unknown's avatar
    rachelmcr · Member ·

    Hi Chris,

    Thanks for reporting this. Can you send me a link to a site where the Gravatars aren’t working? I just tested 1.gravatar.com at http://ipv6-test.com/validate.php and it was working, but if there’s a particular site where you’re having trouble that may help us investigate the issue further.

  • Unknown's avatar
    csamuel · Member ·

    Hi Rachel,

    Interesting, it could be a peering issue somewhere in between – I’m lucky as I have native IPv6 at home but it’s hard to test from elsewhere of course!

    Here’s a pastebin of what I’m seeing..

    http://pastebin.com/U273Bpug

    I’ve contacted my upstream ISP to see if they are aware of issues routing to Edgecast’s CDN.

    All the best!
    Chris

  • Unknown's avatar
    rachelmcr · Member ·

    Hi Chris,

    Thanks for sharing that traceroute. I’ve also asked our team about the issue to see if there’s something happening on our end. I’ll let you know what I find out. :)

  • 762e5e74 · Staff ·

    Hi Chris,

    When you’ve a moment, could you please check if you’re still experiencing the issue ? If yes, then could you please provide a fresh traceroute output to the 1.gravatar.com ?

    Thanks

  • Unknown's avatar
    csamuel · Member ·

    Hi there, happy Christmas all!

    Yup, still happening, here’s the latest traceroute:

    http://pastebin.com/pAbJK7re

    All the best,
    Chris

  • 762e5e74 · Staff ·

    Hi Chris,

    Merry Christmas to you too :)

    Thanks for providing the traceroute. I’ve forwarded it to CDN and they’re looking into it.

    I’ve one question though, do you experience similar issue connecting to CDN over IPv4 network as well, i.e. curl -4 -o /dev/null ‘http://1.gravatar.com/avatar/2bee1359d80010dfb760db173fc402c5’ works for you ? If it does not work over IPv4 as well, could you please provide an IPv4 traceroute output to 1.gravatar.com.

    Thanks

  • Unknown's avatar
    csamuel · Member ·

    Hello there Ashish,

    IPv4 is fine and that URL works, it’s just IPv6 related.

    I’ve also reported to my ISP and I’m waiting for a response. Ah for being on bleeding edge. :-)

    All the best,
    Chris

  • 762e5e74 · Staff ·

    Hi Chris,

    Thanks for the update. We’ve forwarded the details to our CDN provider, who’ll be troubleshooting it with the ISP in question. We’ll let you know if we need more details from your side.

    And, please keep us posted if you hear anything from your ISP in this regard.

    Thanks

  • 762e5e74 · Staff ·

    Hi Chris,

    We’ve heard from our CDN provider, and they’ve replied that this issue has been fixed. Could you please confirm ?

    Thanks

  • Unknown's avatar
    csamuel · Member ·

    Hi Ashish,

    Sadly it appears just the same from here at the moment.

    http://pastebin.com/SRrphqqR

    The s1.wp.com side is actually more of an issue than Gravatar as a lot of the WordPress.com CSS is served via that, so that side ends up looking really broken. :-(

    My ISP has said “We’ve had a bit of a look in to this one and there’s definitely something strange going on” and are still investigating.

    Thanks for chasing this up!

    All the best,
    Chris

  • 762e5e74 · Staff ·

    Hi Chris,

    New year greetings :)

    I’ve heard from our CDN provider, and they mention they’re able to reach your IPv6 address now. Could you please check on your end if it’s working fine now ?

    Thanks

  • Unknown's avatar
    csamuel · Member ·

    Hmm, it’s not, but checking with my VM in the US (connected to IPv6 via an Hurricane Electric tunnel) I see that it works there. The reason is that DNS is giving me different answers in the US to Australia.

    In the US I get:

    csamuel:~# host 1.gravatar.com
    1.gravatar.com is an alias for cs91.wac.edgecastcdn.net.
    cs91.wac.edgecastcdn.net has address 72.21.91.121
    cs91.wac.edgecastcdn.net has IPv6 address 2606:2800:220:bf1:95:a65:51f:1a94

    csamuel:~# host s1.wp.com
    s1.wp.com is an alias for cs82.wac.edgecastcdn.net.
    cs82.wac.edgecastcdn.net has address 72.21.91.111
    cs82.wac.edgecastcdn.net has IPv6 address 2606:2800:220:1c85:99b:1b56:207e:ea5

    Here in Australia I get:

    chris@quad:/tmp$ host 1.gravatar.com
    1.gravatar.com is an alias for cs91.wac.edgecastcdn.net.
    cs91.wac.edgecastcdn.net has address 68.232.44.121
    cs91.wac.edgecastcdn.net has IPv6 address 2606:2800:20d:1047:6cf:353:607:e8a

    chris@quad:/tmp$ host s1.wp.com
    s1.wp.com is an alias for cs82.wac.edgecastcdn.net.
    cs82.wac.edgecastcdn.net has address 68.232.44.111
    cs82.wac.edgecastcdn.net has IPv6 address 2606:2800:20d:559:1b1e:a49:202a:14b5

    I can confirm that if I query the ns1.edgecast.com and ns2.edgecast.com authoritative DNS servers directly they give me different IPv6 addresses in Australia to the US.

    So they may have fixed something, but they’ve not fixed what’s broken here. :-)

  • 762e5e74 · Staff ·

    Hi Chris,

    CDN provider has provided successful traceroute to your IPv6 endpoint from their PoP after doing some changes.

    About the different set of IP addresses in DNS replies when queried from US/AU locations, that seems like GeoDNS in play, pointing you to the nearest PoP.

    Could you provide traceroute outputs to both Australian IPv6 endpoints from your place again, so they can look again ?

    Sorry for this inconvenience.

    Thanks

  • Unknown's avatar
    csamuel · Member ·

    Hiya,

    I can traceroute from home to the IPv6 addresses they provide via DNS for US based hosts, but I cannot to the IPv6 addresses they provide via DNS for Australian based hosts.

    Here’s the pastebin for the Australian IPs – http://pastebin.com/mt6ghnXF

    Here’s a successful traceroute to a US provided IPv6 address for s1.wp.com – http://pastebin.com/D0yu1BF2

    Thanks!
    Chris

  • 762e5e74 · Staff ·

    Hi Chris,

    Looking at the traceroute outputs, it doesn’t look like routing has changed. I’ve passed on the traceroute outputs.

    I’ll let you know when I hear from them.

    Thanks!

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