TRANSPORT pipeline is made up of three different SERVICES:

FRONT end transport service: It does basic message filtering based on domains, connectors, senders and recipients. It only connects with the transport service on a mailbox server and does not backlog any messages locally

Transport service: It runs on all mailbox servers, and it handles SMTP mail flow. It helps in message categorization and content INSPECTION. The transport services routes messages between the Mailbox Transport service, the Transport Service and Front End Transport service. This service does not queue messages locally

Mailbox Transport: This system includes receiving and sending SMTP to the transport service from mailbox using RPC (REMOTE Procedure Call).

Transport pipeline is made up of three different services:

Front end transport service: It does basic message filtering based on domains, connectors, senders and recipients. It only connects with the transport service on a mailbox server and does not backlog any messages locally

Transport service: It runs on all mailbox servers, and it handles SMTP mail flow. It helps in message categorization and content inspection. The transport services routes messages between the Mailbox Transport service, the Transport Service and Front End Transport service. This service does not queue messages locally

Mailbox Transport: This system includes receiving and sending SMTP to the transport service from mailbox using RPC (Remote Procedure Call).