Six generations of Exchange, and the same four problems each time. The products changed completely; the design questions barely moved.
Article collection
Microsoft 365 and Exchange
Messaging, migration, coexistence and administration guidance across Exchange Server, Exchange Online and Microsoft 365.
Published guidance
The last Exchange server is no longer a licensing footnote. Subscription Edition, the dedicated hybrid app and the Graph transition have changed what hybrid coexistence actually requires.
Audits, incidents and reviews all ask the same questions about a tenant. Collecting the answers the same way every time turns an ad-hoc scramble into a comparable record.
A tenant move is an identity project wearing a migration costume. The mailboxes are the easy part; the domain name can only exist in one tenant at a time.
The defaults optimise for collaboration, which is the right default for Microsoft and the wrong one for most organisations. Six settings change the exposure considerably.
Three DNS records that only work in a specific order. Publishing a strict DMARC policy before the inventory is complete is how organisations stop their own invoices arriving.
Message trace answers where a message went. Getting a useful answer depends on knowing which tool covers which window, and on reading the event sequence rather than the final status.
A practical readiness plan for discovering EWS dependencies, controlling temporary access and moving Exchange Online integrations forward.
An architectural view of what changes across Microsoft platform generations, and the operational questions that still need an answer.