Every database event (create a customer, update an ip record, export a DNS zone file etc) in IPplan can trigger an external user defined function or script. This is useful to update and external system like a DNS server once something in IPplan has changed.
You will be required to write your own custom script to do the required action. This script will be called from the user_trigger() function in the ipplanlib.php script. See the comments of this function for more details.
A list of all the IPplan triggers and what information is passed to the user_trigger() function can be found in the TRIGGERS file.