Pre-requisites for Emulating Email Sending/Receiving Activity
The emulation can be performed only by an external agent. This means that at least one external agent should be up and running in the environment for the emulation to occur.
If you want to simulate the mail sending/receiving activity for a sender and receiver in the same location, then you can install and configure a single external agent, and configure this agent to simulate both the email transmission and reception.
On the other hand, if you want to simulate the email communication between a sender in one location and a receiver in another, then you will have to configure two external agents - one per location. For instance, you may want to monitor the email communication between sender firstname.lastname@example.org in Singapore, and receiver email@example.com in California. In this case, you need to install two external agents - one in Singapore and another in California. Then, you should use the agent in the sender's location - i.e., Singapore - to simulate the email transmission, and the agent in the receiver's location - i.e., California - to simulate the email reception.
Note that a single eG external agent can be configured to perform multiple simulations.
For every simulation, two valid mailboxes are required - one for sending emails and another for receiving them. You may want to consider creating a dedicated sender and receiver for monitoring purposes.