Exchange On-Premise to Office 365: Flawless ActiveSync Migration
Microsoft has found a new way to migrate and update active sync URL when we migrate from on premise to office 365.
All on premise migration has always been flawless but when we used to migrate to office 365, we had required to update the active sync device manually if dns pointing to on premise.
With the newly released Exchange 2013 CU8 and Exchange 2010 SP3 RU9, it is possible to update the active sync device with the new URL of office 365.
This is how it works now.
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Migrate the mailbox from on premise to office 365.
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ActiveSync device tries to sync using the currently configured URL which connects to on-premises Client Access server. This can be Exchange 2010 or 2013 CAS.
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This Client Access server further queries Domain controller to check if the user mailbox is present.
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Then Client Access server gets a response from Domain controller that the user mailbox is not found.
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Then Client Access server queries to find the “TargetOWAURL” attribute present on the organization relationship object for the Office 365configuration.
The “RemoteRoutingAddress” attribute present on the remote mailbox which is used to find the correct organization relationship.
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So here Client Access server receives the TargetOWAURL configured on the Organization Relationship.
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Now Client Access server sends the URL in an HTTP 451 response to the mobile device. Device should support HTTP 451 redirection.
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The active sync device tries to sync with the new URL.
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The active sync profile on the device is updated to the Office 365 URL.
More information about this change can be found here.
Let us know more about these 2 attributes.
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TargetOWAURL:
The TargetOwaURL parameter specifies the Microsoft Office Outlook Web App URL of the external organization defined in the organization relationship. It is used for Outlook Web App redirection in a cross-premise Exchange scenario. Configuring this attribute enables users in the organization to use their current Outlook Web App URL to access Outlook Web App in the external organization.
Now ActiveSync migration process also use the same url to connect to your office 365.
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RemoteRoutingAddress:
The RemoteRoutingAddress parameter specifies the SMTP address of the mailbox in the service that this user is associated with.
If you’ve configured mail flow between the on-premises organization and the service, you don’t need to specify this parameter. The remote routing address is calculated automatically. “RemoreRoutingAddress” is a “TargetAddress” Attribute configured on an on premise mail enabled user.
I hope this helps in the understanding this change.
Prabhat Nigam
Microsoft MVP | Exchange Server
Team @MSExchangeGuru
June 19th, 2015 at 8:33 pm
[…] after his mailbox has been moved to Office 365. We have already talked about this attribute here. At the same time this URL should be resolving office 365 […]
September 8th, 2015 at 1:12 pm
hi, we moved users from the cloud back to our on premise server, (we are running a hybrid enviroment) . since then activesync no longer works on accts. any suggestions? all article i can find are about moving it to the cloud
September 8th, 2015 at 2:47 pm
You need to reconfigure the Profile. I think I mentioned that in my hybrid blog when I talked about the reversal of the mailbox move.
September 8th, 2015 at 3:25 pm
ok thx, I looked in that blog and tried that but with no luck. now we are running exchange 2010. would upgrading to 2013 resolve it? I have tried changing and completely resetting up the profile on the phones, neither have worked. weirdly I got it to work completely on one test user I setup but a user that was migrated back last month is still a no go. it sets up but will not send any email or load any. any ideas?
September 27th, 2015 at 6:59 pm
[…] Exchange ActiveSync clients will be seamlessly redirected to Office 365 when a user’s mailbox is moved from on premise to Exchange Online. Exchange ActiveSync clients should support HTTP 451 redirect. We already discussed about this attribute change here. […]
October 1st, 2015 at 2:53 am
[…] Exchange ActiveSync clients will be seamlessly redirected to Office 365 when a user’s mailbox is moved from on premise to Exchange Online. Exchange ActiveSync clients should support HTTP 451 redirect. We already discussed about this attribute change here. […]
January 20th, 2016 at 2:08 pm
[…] don’t need to configure mobile device because Targetowaurl attribute will provide redirection URL. I have tested this and it works but have some patience […]
July 19th, 2016 at 3:35 pm
[…] Exchange ActiveSync clients will be seamlessly redirected to Office 365 when a user’s mailbox is moved from on premise to Exchange Online. Exchange ActiveSync clients should support HTTP 451 redirect. We already discussed about this attribute change here. […]
March 18th, 2017 at 10:30 pm
I have successfully configured Exchange 2013 Hybrid configuration with Office 365. After moving a mailbox to cloud, now Exchange Active Sync does not work. It work perfect using outlook client but android app “Email” does not work. Security Warning “There are problem with security certificate for this site. The name of the site does not match the name of the certificate” Kindly guide me in this regard ASAP. Thanks
March 18th, 2017 at 11:20 pm
Check it resetting activesync application pool helps.