Backup exchange in the branch. Will the users of the branch office be able to send mail through it if the main server at the central site fails?

Question

Microsoft Exchange

Good afternoon, comrades. The situation is this: we want to have a backup exchange in the branch with the same domain name (conditionally @sobaka.ru. Moreover, geographically both exchange servers will be located in different cities and on different subnets, but have ping to each other. Let's say the main one is located in Moscow , backup in Yekaterinburg
The question here is this: if the main exchange server fails, will users in the branch office be able to send mail to each other?

Answer 1

Depends on the architecture you plan.
The short answer is yes.
Create a new website, set up a domain controller, deploy an extension.
You create bases in which boxes of branch users will lie (a dag is not obligatory).
For mail to the world, make a separate send connector.
Balancing of incoming mail can be done by MX - if the main eksch lies then mail will be received by the branch office (if there is a public ip).

Answer 2

If the user's mailbox is located on the branch server and the branch clients themselves connect to it, then mail will work between employees. In a word, it all depends on how you set up the server, Exchange itself allows it.