How to configure Exchange Server 2010 to receive and send mail to the Internet?

Question

Domain Name System

Hello Dear Gurus!
Sorry, straight to the point.
The organization purchased a second-level domain (domain.ru) from a provider and deployed a domain name system with the same domain. Before the domain controller went down, an Exchange 2010 server was configured to serve the domain. Raised the controller, mail goes only within the domain, from the Internet and the Internet does not come / go.
I started digging the Internet, checked the send connectors, addresses, ports, protocol, permissions.
I noticed that the smtpsend and smtp recieve logs stopped coming... The MessageTracking and Connectivity logs are successfully updated, which should indicate that they are working...
Also, the outlook client could not authorize inside the domain, cannot find the server.
Specify which direction to dig

Answer 1

Most likely trust between an eksch and the controller was lost.