Solved

Moving Some Domains from Exchange 2010 to Office 365

Posted on 2016-09-13
6
30 Views
Last Modified: 2016-09-28
We have an Exchange 2010 server with several email domains. We're moving 2 of those domains to Office 365. What do we need to do to maintain mail flow from the remaining Exchange users to the migrated 365 users?
0
Comment
Question by:TechGuy_007
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 9

Expert Comment

by:Ibrahim Benna
ID: 41795970
Will you still have users/mailboxes that will have addresses from these 2 domains? I assume you are planning on setting up a hybrid configuration in order to move mailboxes over?
0
 

Author Comment

by:TechGuy_007
ID: 41796012
I'm sorry, I don't understand your first question. Let's say we have 5 domains on the onsite Exchange server, and we're moving 2 of those domains to 365 entirely - they will not be using the onsite Exchange server at all anymore. We want to make sure that users from the remaining 3 domains don't have issues emailing anyone from the 2 migrated domains. We plan to remove the domains from the accepted domains in the onsite server - just not sure if we need to update x500 addresses / how to do that.

The hybrid configuration isn't working. 365 support could not tell us why or how to fix it, so we're manually creating accounts and importing PSTs to 365 (there are only about 20 users so not too painful).
0
 
LVL 16

Expert Comment

by:Ivan
ID: 41796107
Hi,

for that configuration to work, you would need to:
1. Register those 2 domains to office365.
2. Create user accounts and assign license, so that they have mailbox created.
3. On o365 Exchange, configure those 2 domains as authoritative, create email address policy.
4. Test to see if email is working between those o365 users, via webmail. It should work internally.
5. Reconfigure MX records for those 2 domains to point to o365.
6. On local Exchange, remove accepted domain and email address policy for those users, so that other onsite Exchange users will now use public MX and therefor route email for those 2 domains to o365.
7. Reconfigure Outlook clients to connect to o365.

There will probably be some down time in steps 5-7, so maybe you can do this off work hours or during weekend.

Regards,
Ivan.
0
To Patch or not to Patch? That is the question!

Don't get caught out like thousands of others around the world in the recent Ransomware Fiasco!
Discuss..
- Why it's not a good idea to wait before Patching
- Sensible approaches to Patching discussed
- Add your feedback, comments and suggestions

 
LVL 15

Expert Comment

by:Todd Nelson
ID: 41796294
If the hybrid config is not working, as you say, are you still using AD synchronization?

The unfortunate part is if you are still using on premises mailboxes for the domains you added to O365 you will have to manually set the TargetAddress attribute in AD (if the hybrid config did not work) so Exchange knows that those specific mailboxes may reside elsewhere and forward the messages appropriately to O365.  Can be tricky but doable.

Personally, I would make every effort to get the hybrid working appropriately to make administration relatively easier.
0
 

Accepted Solution

by:
TechGuy_007 earned 0 total points
ID: 41812361
We ended up deleting mailboxes and creating mail users connected to each user's AD profile, then entered the 365 onmicrosoft email address in for the mail user. Workaround, but it works.
0
 

Author Closing Comment

by:TechGuy_007
ID: 41819441
Sought outside help from Microsoft and solved issue outside of EE suggestions.
0

Featured Post

Office 365 Training for Admins

Learn how to provision tenants, synchronize on-premise Active Directory, and implement Single Sign-On with these master level course.  Only from Platform Scholar

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

How to resolve IMCEAEX NDRs in Exchange or Exchange Online related to invalid X500 addresses.
As cyber crime continues to grow in both numbers and sophistication, a troubling trend of optimization has emerged over the last year.
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
how to add IIS SMTP to handle application/Scanner relays into office 365.

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question