Hi
We currently have on-premise email "@mydomain.com" , and an Office 365 plan also using "@mydomain.com" which is linked to a NEW AD environment. So, all users will have new account/username/password but same email address.
At the moment, users in both environments have secondary (unique) email adresses so emails can be forwarded from o365 to on-premise, or on-premise to o365 as necessary.
We are migrating users from on-premise exchange/domain to new o365/domain. All going reasonably well.
But, we have a problem with Autodiscover.
autodiscover.mydomain.com points to the on-premise setup and hasn't been working properly etc.
We thought we could point autodiscover.mydomain.com to the o365 environment, and then all new client profiles of users we migrate get the new settings, and hey presto everything works. (in tests we've been adding manual entires to local hosts files in order to resolve autodiscover.mydomain.com to the o365 environment).
BUT - existing clients still connected to the on-premise system still seem to be using "autodiscover" as once we changed DNS users started getting certificate errors and asking to log on to the o365 environment. We thought, incorrectly, autodiscover would not be used once the clients were set up.
SO - what do we do? How can we cope with autodiscover.mydomain.com pointing to both o365 for migrated people, and on-premise for non-migrated? Can it be done? Or do we need to modify local hosts on every client we migrate and manually set up iPhones etc?
Ideas welcome!