1. Open the DHCP management console & expand the server 

2. Expand the scope where the phones are connected; typically, there will only be one scope on most small business networks 

3. Go to ‘Scope Options’ 

4. Right-click and select ‘Configure Options’

5. Scroll down to Option 66 and select the box 

6. Paste the URL above into the ‘String value:’ field 

7. Click OK