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IPv6 issues with Office365/Outlook 2016

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IPv6 issues with Office365/Outlook 2016

This seems to be a common issue with Comcast and Office365 from searching online [1], but the suggested fixes (prefer IPv4 over IPv6) don't seem to be working for me. I'd like to try to understand exactly what's happening here, so I can figure out the root cause and then hopefully find the right person to address it. Disabling IPv6 on my computer or router is not an option I'd like to pursue.

 

The short version of the issue: Outlook 2016 regularly goes into a "Trying to connect..."/"Disconnected" state on my Office365 account. Digging deeper, it seems that outlook.office365.com (the endpoint for the mail account) stops being resolvable via IPv6 DNS. This state comes and goes -- sometimes it works great, and then sometimes it stops. The weird thing is that only seems limited to the outlook.office365.com domain -- if I try to resolve google.com via IPv6, for example, it works just fine.

 

Modem: Arris TM822G. It shows it is getting IPv6 leases in the modem status page.

Router: Asus RT-N66U with Merlin firmware (380.58). IPv6 connection type is Native with DHCP-PD enabled.

Computer(s): Windows 10

 

When I go to a site like http://test-ipv6.com/, I get a 10/10 for IPv6 readiness. (Public IPv6 address starts with 2601:602...)

 

So, I think my overall IPv6 configuration is correct.

 

When in this "failure" state, here's the output of a nslookup (trying to use Google DNS via IPv6, but same result with Comcast DNS or other public servers):

 

nslookup -debug outlook.office365.com. 2001:4860:4860::8888
------------
Got answer:
    HEADER:
        opcode = QUERY, id = 1, rcode = NOERROR
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 1,  authority records = 0,  additional = 0

    QUESTIONS:
        8.8.8.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.6.8.4.0.6.8.4.1.0.0.2.ip6.arpa, type = PTR, class = IN
    ANSWERS:
    ->  8.8.8.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.6.8.4.0.6.8.4.1.0.0.2.ip6.arpa
        name = google-public-dns-a.google.com
        ttl = 21599 (5 hours 59 mins 59 secs)

------------
Server:  google-public-dns-a.google.com
Address:  2001:4860:4860::8888

DNS request timed out.
    timeout was 2 seconds.
timeout (2 secs)
DNS request timed out.
    timeout was 2 seconds.
timeout (2 secs)
*** Request to google-public-dns-a.google.com timed-out

Since this impacts a lot of other users, I'm thinking it is not related to my modem or router (since IPv6 tests pass even in this state). I've even set my DNS to use Google DNS (via IPv6) but it's still not resolving. Is this a lower level networking issue on the Comcast side? A DNS issue on the Microsoft side? Help!

 

[1]

http://www.windowsobserver.com/2013/11/26/office-365-connectivity-issues-try-disabling-ipv6-on-your-...

https://community.office365.com/en-us/f/158/t/430231

https://community.office365.com/en-us/f/158/t/291336

https://www.reddit.com/r/Comcast/comments/4aov4a/can_somebody_on_comcast_do_a_ping_for_me_any_ipv6/?

 

Diamond Problem Solver

Re: IPv6 issues with Office365/Outlook 2016

If your running this on a laptop, can you take it to another friend's house with Comcast service, or a xfinitywifi connection to test it?  Will it work when you bypass the router?

 

We run several machines here, including a win10 / outlook 2016 without issues on Office 365, and I also have several customers with Comcast internet and Win 10 / Outlook 2016 on Office 365 without issues.

 

 

 

New Poster

Re: IPv6 issues with Office365/Outlook 2016


JayInAlg wrote:

If your running this on a laptop, can you take it to another friend's house with Comcast service, or a xfinitywifi connection to test it?  Will it work when you bypass the router?

 

We run several machines here, including a win10 / outlook 2016 without issues on Office 365, and I also have several customers with Comcast internet and Win 10 / Outlook 2016 on Office 365 without issues.

 


This is a desktop, unfortunately, so I can't easily try another network. Since the repro is intermittent (it's working at the moment), I don't know if I can bypass the router long enough to get a repro -- I have other devices on the network that require network connectivity.

 

Another one of my laptops on this network also has Win10/Outlook 2016 connecting to the same mail server -- but it uses IPv4 and does NOT have this issue at all. So it definitely seems IPv6 related. To wit, I temporarily disabled IPv6 in the network adapter on this computer (desktop) and while it was disabled had no connectivity issues with Office365, but that's not a state I can run in long term.

Contributor

Re: IPv6 issues with Office365/Outlook 2016

Did you ever make any progress on this.  I put IPv6 on my router (DD-WRT) just yesterday and have been experimenting, and most things just work. Except outlook, sometimes.

 

I have two Windows 10 systems, and each has two different exchange accounts, one Office 365, one a corporate account.  The corporate account is IPv4 only, and always works.  Somewhat randomly, the Office 365 account goes into a disconnected state, but interestingly NOT at the same time on the two computers, but different times.  Same account, same router, same DNS settings.

 

I haven't dug into it.  I thought at first it was only happening when the router rebooted (I did that a lot at first getting it going), and I thought IPv6 connectivity was dropping.  But much of today I was working on other (not network related) issues and noticed one computer working, the other would not.

 

Invariably rebooting the computer will fix it, at least for a while.  Closing and opening outlook, ipconfig/flushdns does not fix it.

 

This note is the first time I had a hint it may be comcast related.  I'm not exactly sure how, as I think i'm resolving against a local cache (in fact wouldn't you be also?). 

 

I'll spend more time on it next time it acts up (it's been maybe a half dozen times between the two computers in two days), but if you found anything out would be curious.  

 

So far that's the only thing that doesn't seem to be working correctly that shoul dbe using IPv6.

 

Highlighted
Diamond Problem Solver

Re: IPv6 issues with Office365/Outlook 2016

Try a different router with the original firmware or bypass the router for a direct connection to the modem.  I have many customers running Office 365 on Windows 10 without issues on a Comcast connection, with a variety of routers or gateways.

New Poster

Re: IPv6 issues with Office365/Outlook 2016

I too, am having the same issue. Disabling IPv6 resolves it, but is not something I prefer to do on hundreds of computers. Thanks in advance for any help.

New Poster

Re: IPv6 issues with Office365/Outlook 2016

I am experiencing the same issues with Outlook 2016 not connecting to the exchange server "most of the time".  Sometimes it does connect, but usually does not. Please help!!

Expert

Re: IPv6 issues with Office365/Outlook 2016

Year and a half old dead thread now being closed. Please create a new topic of your own here detailing your issue.



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