Continuity: keep working with email when the mail server is down

Continuity makes sure that incoming email is not lost while the mail server behind it is unreachable. This covers outages at Microsoft 365, at an in-house Exchange and at any other target system Conbool delivers to.

Conbool receives the mail first as a gateway anyway. If the target fails, continuity holds the mail, makes it readable and delivers it once the target answers again. There is no second MX record, no switch-over button and nothing that would first have to be activated in an emergency.

What happens when the mail server fails

Without continuity, three things happen. The delivering server retries for a few hours and then gives up, the sender receives a non-delivery report, and nobody in the company sees in the meantime who has written. The mail is not gone, but it is invisible and partly lost.

With continuity it stays visible. Every incoming message lands in a continuity store from which it can be read, answered and forwarded in the browser. After recovery everything goes to the actual mailbox automatically.

Two levels

The difference lies in the answer to the delivering server.

Level 1 continues to answer with a temporary rejection. The server on the other side keeps the message and tries again later, exactly as without continuity. In addition a readable copy is created at Conbool. Nothing can be lost, because the message exists twice.

Level 2 accepts the message and thereby takes responsibility for it. The server on the other side is done and deletes its copy. For the sender the delivery looks normal, and they notice nothing of the outage.

Level 2 is the actual purpose of the product, and it is the level with the obligation: from the moment of acceptance there is only one copy, and it lies with Conbool. That is why it is enabled per tenant individually.

What continuity is not

It does not replace a mailbox. Calendar, contacts, tasks and the existing message holding stay in the failed system.

It does not replace an archive either. The continuity store holds the messages of the outage period and clears up afterwards. Anyone who needs the history permanently needs the archive.

And it only works inbound. Outgoing mail from the failed system cannot be caught by Conbool, because it never reaches the gateway in the first place. For sending during an outage there is composing in the continuity view.

Read on

• Preparation: the two prerequisites that cannot be created during an outage.
• During an outage: what the continuity view can do.
• After the outage: how the mail catches up.
• Settings: mode, retention, visibility, maintenance window.
• When something is wrong: the most common questions during a running outage.