Cisco Cisco Email Security Appliance C390 사용자 가이드

“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. The non-queueing listener accepts a message, and then immediately 
deletes it without saving it.

Use a queuing listener when you are interested in measuring the performance of 
the entire injection portion of your message generation system. Use the 
non-queueing listener when you want to troubleshoot the connection from your 
message generation system to the appliance. 

For example, in 

, 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. 

This is a test message.

Run through another debug session? [N]>