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Can I use Load Balancer for Hybrid Exchange redirection?

I am replacing by Exchange 2010 Hybrid Exchange server with Exchange 2016 Hybrid servers.  I have no on-premise mailboxes -- only Office 365 mailboxes.  The on-premise servers are for bulk and anonymous sending, management,  web redirection to Office.  In the past I've had trouble with IIS reconfiguring itself after patches and updates.  I'd like to omit IIS activities from configuration and simplify.  Would it be possible to setup a load balancer to redirect mail.domain.com to outlook.com/owa/domainname.com and not configure IIS.  I know the smtp sending wouldn't be effected, but I'm not clear on autodiscover,activesync, etc. and how they might be effected. All the web articles I'm seeing show setting virtual directories for autodiscover,activesync,owa, etc. - what is the purpose of these virtual directories and are they necessary for a no on-premise maibox hybrid install.What do I need to test for on-premise clients? Thanks in advance.
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MaheshArchitect
Distinguished Expert 2019

Commented:
I don't see IIS is coming in picture here unless you are using your custom onpremise URL to redirect to Exchange online

Normally we use outlook.office365.com/mail
OR
login.microsoftonline.com
C EmmonsAdmin

Author

Commented:
I talked to Microsoft.  At first I felt like I didn't need virtual directories, but then later engineers suggested I set them up -- and they realized I had no on-premise mailboxes -- so I wondered if I was missing something.
MaheshArchitect
Distinguished Expert 2019

Commented:
Probably you can remove hybrid config and just keep AD sync in place

No need to redirect any URLs to O365

Use native O365 URL for owa access

I believe your autodiscover is pointing to O365, in that case set onpremise SCP to $null

Get-Clientaccessserver | Set-ClientAccessServer -AutodiscoverinternalURI $null

Now autodiscover will work with DNS discovery and you simply need autodiscover record
C EmmonsAdmin

Author

Commented:
How does activesync work from Internal network?
Architect
Distinguished Expert 2019
Commented:
The same way as it works from internet as you will create CNAME record for auto discover record with internal DNS as well which will instruct activesync how to connect to exchange online
You can find record details in domain setup page in O365 admin center
C EmmonsAdmin

Author

Commented:
okay, thanks.