Things You'll Need

Instructions

1

Click the "Start" button on the Windows 7 computer PC desktop and click "Programs," and then click "Accessories." Right-click the command line icon in the menu and then click "Run as Administrator." Enter "telnet 1.1.1.1" in the command line window that appears, substituting the "1.1.1.1" with the IP address of the Cisco switch and press the "Enter" key. Enter the telnet password and tap the "Enter" key.
2

Enter "enable" at the command prompt and tap the "Enter" key. Enter the Cisco switch Privilege Exec password and tap the "Enter" key. Type "int vlan X," replacing "X" with the number of a VLAN for which you wish to block DHCP requests.
3

Type "no ip helper-address x.x.x.x" replacing the "x.x.x.x" with the IP address of the DHCP server servicing hosts on the Cisco switch. Press the "Enter" key. Type "end" and press the "Enter" key.