I run Debian Wheezy on a old Acer Aspire One ZG5 model netbook as a server. I have a printer shared to all my other systems and I'm worried about security. On the server I have IPtables set up to block everything that hasn't been initiated by the server itself and I opened ssh, cups (631), AVAHI (assumed 5353 for airplay printing). I just want to make sure no one but my trusted systems can print, that no one but me can get in a change CUPS settings via web or otherwise, and that no one can use a obscure CUPS hole to mess with my server. I have one iPhone, one android tablet, and two Debian Wheezy Laptops I want to share my printer with. I'm unsure how to go about securing CUPS or what even is the best security to use with CUPS.