The install and uninstall scripts are executed in the webapp directory for the app, say, for application
@HDA_DOMAIN@ --> home.com (the domain)
@HDA_NETMASK@ --> 255.255.255 (the netmask)
@HDA_NICKNAME@ --> <yournicknick> (the nickname of the dyndns- <nick>.yourhda.com)
please don't assume much and use as generally as possible,
as these may support more general settings in the future
(like a more general netmask, etc.)