Hi,

I currently have an environment of coexistence between Exchange 2010 and O365 and I want to migrate Exchange 2010 to new organization Exchange 2013 by keeping O365. Final photo: new Exchange 2013 Organization with the same O365.

Have the Autodiscover service published in the public DNS to allow connections from outside the organization. Internal domain DNS I have the Autodiscover service pointing to Exchange 2010.

Is possible to use the same autodiscover in internal DNS to point to Exchange 2013 without breaking the connection of users who are still in Exchange

Neil Johnson wrote a blog that explains Exchange/Office 365 coexistence in pretty good detail.  If you follow his recommendations, you should come out OK.  http://blogs.technet.com/b/neiljohn/archive/2011/08/15/office-365-hybrid-deployment-exchange-rich-coexistence-sharing-availability-free-busy.aspx  And before you say "This is for sharing free & busy", keep in mind that if you can cover this part of a shared environment, you are covered for Autodisc

Hi Jesus,

Thank you for your question. 

If Exchange 2010 and Exchange 2013 are in the same domain, we could point Autodiscover record to Exchange 2013, Exchange 2013 will proxy the request to Exchange 2010 when the Exchange 2010 connect to their mailbox.

If Exchange 2010 and Exchange 2013 are not in the same domain, we could not achieve it.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim