You can also block access to all websites except those you specify.
Press the F5 key to access Advanced setup.
Click Web and Email → Web access protection and expand URL Address Management. Click Edit next to Address list.
Click Add, type the links of the sites that you want to block and then click OK. Click OK in the open windows to exit Advanced setup.
Follow the instructions in the section above to add a wildcard (*) to the list of blocked addresses.
Select the List of allowed addresses and follow the instructions from steps 4-5 above to add the URLs for websites you want to allow.