Transport Agents

The concept of Microsoft Exchange 2007/2010/2013/2016 organization bases on modified SMTP events structure. The messages are processed on the stages of SMTP transport by transport agents that perform different functions.

When a message comes to the server, it is transferred through the SMTP transport network, and on each SMTP event several transport agents can be registered. Transport agents can access to the the messages and perform specific actions on them. Each transport agent performs its own check and transmit the message to the next agent. So, transport agents can react on the events related to the receiving of the message and its further routing.

There are two different types of transport agents:

•SMTP Receive Agent – allows reacting on events of message receiving.

•Routing Agent – allows reacting on events of message routing.

Exchange Server 2007/2010/2013/2016 allows to set the priority to transport agents and manage the order of agents applied to the messages. Therefore, the sequence of transport agents is defined not only by the order of the events, but also by their priorities within the same SMTP event.

Transport agents allow to implement special software into the Exchange Server for email processing, anti-virus and anti-spam check.

Dr.Web uses transport agents to check for viruses and spam only the mail received via SMTP (in case you have "Anti-Virus&Anti-Spam" license).