For Veeam Backup & Replication, this guide will show you, step by step, how to create and implement a disk-based immutable backup repository from scratch.
In this part: Tighten security on the Linux server (MFA/2FA).
This article will guide you how to configure your Exchange server to use external DNS servers for external DNS lookups. This is for Exchange 2013 or higher versions. It is recommended to configure the DNS servers for flawless mail flow.