Hello and Welcome to LinuxQuestions,
The best thing to get in your case is a sound amount of self discipline
, no offense. If you have root access on your machine then having your colleague put something in place on your computer will only be for a limited time effective. On the other hand if you don't have access to the firewall (assuming you have one in your office) or your router (assuming it's a type on which you can configure ACL) and your colleague or system administrator does, then I'd ask them to forbid access to the internet from your computer identifying it by MAC address.
Looking forward to your participation in the forums. Have fun with Linux.
Kind regards,
Eric