You can change the port on which the built-in web server runs.
This file is in the cf_root\runtime\servers\default\SERVER-INF directory in Windows, and in the cf_root/runtime/servers/default/SERVER-INF directory on UNIX.
<service class="jrun.servlet.http.WebService" name="WebService"> <attribute name="port">8500</attribute> <attribute name="interface">*</attribute> <attribute name="deactivated">false</attribute> ... </service>
Note: Make sure that the deactivated attribute is set to false.