begin [driver-type]
Exim moves mail... it's an MTA... that's what an MTA does. The parts of Exim that actually do the moving are the Exim Drivers. Exim drivers come in three flavors:
- Router - What directs the message
- Transport - What puts the message
- Authenticator - What keeps everyone sane
Each type of driver has a seperate section in the configuration file. Each section MUST begin with the begin declaration.
Only definitions of the type in the begin declaration can be in that section. Also, there is only one of each. One section for routers that only contains router definitions, one for transports that only contains transport definitions and one for authenticators that only contains authenticator definitions.