Aastra Telecom 9143i Series User Manual

6-22

41-001160-03, Rev 00, Releaes 2.4 

IP Phone Administrator Guide

The Blacklist Duration feature helps to reduce unnecessary delays during proxy/
registrar server failures, caused by the IP phone repeatedly sending SIP messages 
to a failed server. If you enable this feature, then whenever the IP phone sends a 
SIP message to a server, and does not get a response, the phone automatically 
adds the server to the blacklist. The IP phone avoids sending messages to any 
servers on the blacklist. If all servers are on the blacklist, then the IP phone 
attempts to send the message to the first server on the list. 

You can specify how long failed servers remain on the blacklist in the IP phone’s 
configuration file or in the Aastra Web UI. The default setting is 300 seconds. If 
you set the duration to 0 seconds, then you disable the blacklist feature. 

Use the following parameter to configure the Blacklist Duration in the 
configuration files:

For the specific parameters you can set in the configuration files for setting Blacklist Duration, see Appendix 
A, the section, 

Draft 1