Policy on users of Internet sharing on Mac OS X Mountain Lion I have an ADSL Modem directly connected to my Mac 10.8.2 in bridge mode, the PPPoE connection is initiated by Mac and internet is shared to user computers / mobiles using WiFi.

Question:
Can i limit the speed of a specific IP / Mac address or other restrictions like blocking website ?

Regards
There is not a decent way to do this using OS X's Internet Sharing feature. It is not designed to be a fully-fledged router. I recommend that you purchase an inexpensive router that is capable of 802.11n and WPA2 encryption and use this to share to all devices on your network. This will have a side benefit of protecting your Mac from external attacks.