Publishing Exchange Post Hybrid Migration

[colly72]

Hi All,

 

We've successfully migrated all our Exchange 2016 Mailboxes to Exchange online, using hybrid. Our mx records point to O365. We will be changing our DNS autodiscover records to O365 in the next few days. Once this is done, are they any requirements to publish our existing Exchange Server via our Firewall? I've read somewhere that basic https access is required but any advice would be appreciated.

[Gideon_Kay]

Hi,

 

It would depend on there still being services that are hosted on-site or not i.e. public folders etc. If everything is in the cloud now I don't see a need for a patch back to the on-site system.

 

Hope this helps

 

GK

[colly72]

Hi,

 

It would depend on there still being services that are hosted on-site or not i.e. public folders etc. If everything is in the cloud now I don't see a need for a patch back to the on-site system.

 

Hope this helps

 

GK

 

Nothing on-site, other than a need to retain a basic Exchange Server for management, as we use Azure Ad Connect to sync. I'm sure I read somewhere that we still need to allow incoming https to the on-prem Exchange but I can't seem to find any definitive advice on it.

[psydii]

We’ve restricted external inbound so only MS365 services can talk to it.

 

Not noticed any quirkiness yet.

[DrCheese]

Aye I flattened 443 inbound after the recent vulnerabilities, zero issues since.

[chaplic]

You dont need anything. In fact if you are comfortable manipulating exotic AD attributes like MsExchRecipientDisplayType you don't need your exchange server turned on. You should un-hybrid as well, for tidyness and ensure your domains in O365 and authoritative not internal relay.