Exchange Online
In short
Exchange Online is the mail service in Microsoft 365. It runs mailboxes, calendars and contacts in the cloud, filters incoming mail and governs who can reach which mailbox. It is included in effectively every Microsoft 365 business plan.
What it takes over
Operations. No mail server of your own, no weekend maintenance windows, no question about whether mail still arrives during a power cut. Plus filtering of spam and malicious attachments.
It also takes over access logic: delegates, shared mailboxes, forwarding rules. Precisely the cases that, on a self-run server, nobody ever documented properly.
What it explicitly is not
A backup. Microsoft runs the service with high availability, but availability is not recoverability: a mail deleted eight months ago is not sitting in a recycle bin.
If mail is a business record — and in many companies it is exactly that — it needs its own backup with a defined retention period.
The mistake that costs most
Forwarding rules nobody remembers. An automatic forward to an outside address is the quietest way for correspondence to leave a company, and the most common leftover of a compromised account.
It needs checking on a schedule, not once. The same goes for mailbox permissions, which get added at every role change and removed at none.
How we handle it
We set up mailboxes, rules and permissions so they stay legible later, and we review forwarding rules as a fixed item rather than on request.
Operations and hardening: Microsoft 365 and IT security.
Related terms
A term in your quote that nobody explained?
In a strategy call we translate the offer in front of you — even when it did not come from us.