webapp. question

[shwein]

hi all, i have recently been asked to write a online-order app for a small business. question: is it possible to connect to an app that runs on the business' computer through a php-page(or asp,...) on an externel server?
my isp works with dynamic ip-adressing. I just want to know if thats 'do-able'?
if you need more info, please ask...
thx