In this module, you will examine the components of mail flow, and you will learn how to manage your mail flow, which is a crucial task for every Exchange administrator. You will study the differences between managing mail flow in Exchange Online, Exchange Server, and Exchange Hybrid deployments. From managing mail flow, you will transition to troubleshooting mail flow issues such as emails not being routed correctly in or outside your organization, or when secure connections cannot be established successfully. Yo will learn about the tools Microsoft provides to help you find the root cause of your issues and fix your mail flow. You will then transition from troubleshooting mail flow to troubleshooting transport issues, such as network-based issues, connector and agent issues, and architectural issues, as well as how to troubleshoot in coexistence. Finally, you will learn how to check event, protocol, and tracking logs when all troubleshooting for service availability and message transport has finished and an issue still persists, or if you must find historical data about issues in the past.