This article explains the working of SMTP Connectors and new SMTP topology in the exchange server 2007 when compared to the previous versions. Simple Mail Transfer Protocol is a protocol used for sending messages between different servers. Because most email systems that are connected to the internet uses SMTP as a messaging standard. In exchange server 2003, SMTP relies on the service provided by the Windows OS, whereas in exchange 2007 has its own built in SMTP with interesting new features.
In exchange, the SMTP connectors are the logical representations of connections between a source and destination server. In previous version of exchange, SMTP connector is used for both incoming and outgoing message flow, i.e. two way communications for message flow. But in exchange server 2007, the concept of the SMTP Connector is classified into two types Send Connector and Receive Connector. Each of these types of connector represents a one way communication.
1. Acts as an incoming point for SMTP traffic.
2. Actively listens for all incoming connections.
3. The parameters like Number of active connections allowed, Maximum incoming message size and Maximum recipients per message can be set in the Receive Connector.
1. Used for relaying outgoing SMTP communications.
2. It is not scoped to single server or single point, the end message is addressed to remote destination and reaches the appropriate Connector.
Hope the above is informative.