TFTP Option Cisco UC500

To get your Cisco IP Phone to connect correctly over a VPN, you must configure the local DHCP server (either a router, Windows Server, or other) to hand out Option 150, which is the option for TFTP Server. All Cisco IP Phones need to know the TFTP server address of their main unit (in this case a UC520). To configure a Cisco DHCP server to hand out this address:

1. Telnet or console into the router.
2. Type 'enable' and hit enter.
3. Type in the enable password and hit enter.
4. Type in 'conf t' and hit enter.
5. Type in 'ip dhcp pool poolname' and hit enter.
6. Type in 'option 150 tftpserveraddress' and hit enter.
7. Hit the CTRL and the Z keys on your keyboard to exit configuration.
8. Type in 'write mem'.
9. Exit telnet or console session.

Note #1 - these instructions assume you already have a working Cisco DHCP server on the router in question. The poolname is the existing name of the DHCP pool.

Note #2 - tftpserveraddress is the IP address of the TFTP server handing out phone information.