Disable network device for specified period of time
Selfcontrol

Selfcontrol is an app build for a different purpose, it disables your network connectivity for a certain amount of time to keep you from visiting social websites and keep you more productive. It makes it possible for you to create a white-list or a black-list to allow or block certain ip-adress/sites.

So I login to the server, set Selfcontrol to 1h. Now my internet connection from my server is disabled for 1h and will automatically come back afterwards.