User Guide

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AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 40 Testing and Troubleshooting
Using the Listener to Test the Appliance
Figure 40-3 Output for the Trace Page (2 of 2)
Using the Listener to Test the Appliance
“Black hole” listeners allow you to test your message generation systems and to also get a rough measure
of receiving performance. Two types of black hole listeners are queueing and non-queueing.
• The queueing listener saves the message to the queue, but then immediately deletes it. Use a queuing
listener when you are interested in measuring the performance of the entire injection portion of your
message generation system.
• The non-queueing listener accepts a message, and then immediately deletes it without saving it. Use
the non-queueing listener when you want to troubleshoot the connection from your message
generation system to the appliance.
For example, in Figure 40-4, you could create a black hole listener “C” to mirror the private listener
labeled “B.” A non-queueing version tests the performance path of the system from the groupware client
to the groupware server to the appliance. A queueing version tests that same path and the appliance’s
ability to enqueue messages and prepare them for delivery via SMTP.