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IPV6 and outlook 365

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IPV6 and outlook 365

We are using Outlook 365 Server for our businesses(my Wife and I). We are using Outlook 2103 and Outlook 2016 as clients on our computers.  For the last year we had occasional Loss of connectivity which we could not resolve.


On Apr 7, 2016  after a Microsoft automatic update,  both of us on all our PC we totally lost the connectivity.  We still had connectivity on our phones and through the Web interface for Outlook.  the problem was limited to Outlook application either 2013 or 2016.  After hours of research, we finally found that we had to Disable IPV6 from our NIC.  By disabling the IPV6 and forcing all our traffic to use the IPV4 the connectivity get restored.


To test use the following procedure:

Using a Cmd Window Ping Office.Outlook365.com.  If the request times out it means that the DNS is unable to resolve the address.  Then using the Network Adapter page, UnCheck the IPV6 option. 

Then In The CMD window, Flush the DNS and Ping Office.Outlook365.com. Now the DNS forces the connection to use IPV4.  if this is your problem now the ping should be successful.  If not then you may have other issues.


This problem appear to be old as I found thread dating back to 2013.  According to a few threads I found the issue is somekind of disagreement between Comcast and MIcrosoft on IPV6 implementation.  Not sure I understand the detail. but in a long run I do not care.

What I need is for Comcast and Microsoft to fix the issue that is now more than 3 year olad and as IPV6 is becoming more and more used I will need the IPV6 to be enabled.  


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