How can I configure isc dhcpd to provide option 150 for Cisco phones?

Cisco phones use the proprietary option 150 to tell the phone what server to contact for configuration information.

How can I provide this option using the ISC DHCP server on Ubuntu?

2 Answers

In order to provide option 150 (or other custom options) two configuration entries are required, first, in the top level of the configuration file located at /etc/dhcp/dhcpd.conf you need to define your custom option:

option voip-tftp-server code 150 = { ip-address }; 

Then, in the subnet stanza for where you need to provide the information you'll configure the option with the appropriate value.

subnet 192.168.0.0 netmask 255.255.255.0 { [...] option voip-tftp-server 10.101.0.10; } 

If you place the option definition in the subnet stanza then dhcpd will not work.

It can be:

option tftp-servers code 150 = array of ip-address;

option tftp-servers 10.20.10.1, 10.20.11.1;