Link to home
Start Free TrialLog in
Avatar of Jeff Rodgers
Jeff Rodgers

asked on

Hybrid Office 365 with Exchange 2013 - Mail delivery to all stops when server is down

Looking for a solution or a workaround.   I work for a rural company which is sometimes subject to power issues and internet connectivity issues.   Our environment is a Windows 2008 R2 level domain with Exchange 2013 and runs Hybrid with Office 365.

When life is good, the power is on and the internet is working,  everything works gangbusters.  Fast, peppy, consistent etc...  I am satisfied that the configuration is basically correct.  BUT something is still missing here...or maybe I am missing something.

When the onPrem Exchange server is down or inaccessible,  mail flow stops for everyone even though most of my clients are on Office 365 ( 100 out of 120 accounts are cloud based with only a few smaller accounts in house (service accounts, cleaning supervisor).  

I have verified that the mail flow is thru Office 365 to the in house mail server and according the the Admin portal on Office 365,  all the DNS records are correct.

What do I need to do to allow, the Office 365 email accounts to function even when the OnPrem server is inaccessible?
Avatar of Vasil Michev (MVP)
Vasil Michev (MVP)
Flag of Bulgaria image

So the MX record points to EO and  the mail flow is broken when the on-prem server is down? Can you show us an NDR? And a message trace from O365?

You can always use the user@tenant.onmicrosoft.com aliases for delivery, although it's not really practical...
May I ask why you are keeping a Hybrid Environment?  

If most of your mailboxes are accessed via the Internet why even keep an on-premise Exchange Server?
Avatar of Jeff Rodgers
Jeff Rodgers

ASKER

For Vasil - the unusual thing is that the messages appear to queue in Office 365, but are not delivered to the clients until the onPrem server is back online.   There are no NDR's generated.  

For Jeffrey - we have inhouse applications and an ERP solution that require an onPrem exchange server.  We also have some term users who only need limited email access.  Our executives have asked us not to spend additional money on licences for these employees.
SOLUTION
Avatar of Jeffrey Kane - TechSoEasy
Jeffrey Kane - TechSoEasy
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
I have verified that it is the correct mx record and points to *******.mail.protection.outlook.com

There are no other MX records specified for our domain.
Sooooo you have centralized mail transport enabled? (the second diagram here: https://technet.microsoft.com/en-us/library/jj659050(v=exchg.150).aspx). I can bet that you dont really need that option :)
Interesting,  the Centralized Mail Transport was enabled.  I have disabled it as it is not required.  Was this perhaps what was holding up the works?

When I use Powershell to view the hybrid configuration, it shows that the centralized transport is removed, but still shows SecureMail as one of the options listed under features.

Is this expected?
ASKER CERTIFIED SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Vasil's explanation and solution was the correct solution.   Thank you.

Jeffrey,  I have awarded you points for your help and well because it's a Jeff thing.

Thanks for helping get this resolved quickly.

Holiday's Best to you both!