Exchange 2013 ActiveSync redirection to Exchange 2010 servers


We have introduced an Exchange 2013 server into our environment.  We updated our firewall to point incoming HTTPS services away from our 2010 CAS to the new 2013 server.  Everything worked fine, OWA logins for Exchange 2010 mailboxes redirected from Exchange 2013 OWA to Exchange 2010.

ActiveSync did not work through 2013 for Exchange 2010 mailboxes.  Does the "External URL" need to be updated within Exchange 2010 for this to pass through?  Could someone walk me through possible modifications that will need to be made within our environment to pass this ActiveSync traffic successfully?

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MASEE Solution Guide - Technical Dept HeadCommented:
Did you set the external URLs of active-sync in Exchange2013?
Clear the external URL of Exchange 2010 server.
lighthousekeeperAuthor Commented:
I did not do either of those.  Is that all that is required?  Thanks.
MASEE Solution Guide - Technical Dept HeadCommented:
Will SzymkowskiSenior Solution ArchitectCommented:
The correct way to configure your URL's for ActiveSync is the following...

Using Split DNS Internally


Exchange 2013
External URL =
Internal URL =

Exchange 2010
External URL = $null
Internal =

Not Using SplitDNS


Exchange 2013
External =
Internal =

Exchange 2010
External = $null
Internal =

Exchange will need to proxy all of the requests from Exchange 2013 to 2010.


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