How does DeploymentPro (legacy) bypass Autodiscover?
The Autodiscover service for Exchange 2007+ allows users to automatically connect Outlook 2007+ and mobile devices to Exchange by simply providing an email address and password. It also provides access to certain features of Exchange to Outlook 2007+ clients.
When migrating from one version of Exchange to another, it is not possible to have Autodiscover in place for two environments at once. There are a couple of scenarios for bypassing the Source Autodiscover in order to successfully configure a new Outlook profile for Office 365.
1. On-Premises Exchange to Office 365 Exchange Online cutover migration:
If migrating from On-Premises Exchange to Office 365, and the computers are joined to the domain, Outlook will try to automatically configure the profile using SCP lookup (settings from Active Directory). Then it will query internal DNS, then look to External DNS settings. The new profile will configure successfully, but it will automatically connect to the Source Exchange environment.
2. If performing a staged/batch migration from On-Premises or Hosted Exchange, it will be necessary to have some Outlook users connected to the Source environment and some users connected to Office 365. The users who need to connect to Office 365 will need to bypass Autodiscover.
There are several different ways that Outlook tries to connect to the Autodiscover service. Their order and priority is as follows:
SCP lookupHTTPS root domain queryHTTPS Autodiscover domain queryHTTP redirect methodSRV record query
DeploymentPro (legacy) automatically makes the following registry edits to bypass Autodiscover and hard code the Office 365 server settings into the Outlook profile to ensure that users can begin using the Office 365 profile right away.
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\AutoDiscoverPreferLocalXML, 1ExcludeHttpsAutodiscoverDomain, 1ExcludeHttpsRootDomain,1ExcludeSCPLookup, 1ExcludeSrvLookup, 1ExcludeSrvRecord, 1