Page 123 - Asterisk™: The Future of Telephony

ddns-update-style interim;
ignore client-updates;
subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.1;
option subnet-mask 255.255.255.0;
option domain-name-servers 192.168.1.1;
option tftp-server-name "192.168.1.100";
option ntp-servers pool.ntp.org;
option time-offset -18000;
range dynamic-bootp 192.168.1.128 192.168.1.254;
default-lease-time 21600;
max-lease-time 43200;
}

Alternatively, you can configure from the phone itself to manually use
an alternative TFTP server than that given by the DHCP server. To do
so, press the settings button, (on the G version of the Cisco phones, this
looks like a square with a check mark inside of it; G means Global). You
will then need to unlock the settings by pressing the 9 key. The default
password is cisco. Once the phone is unlocked, press the 3 key on the
dialpad to enter the Network Configuration. Scroll down to option 32
and set the Alternate TFTP to YES. Then scroll up to option 7 and enter
the IP address of the TFTP server you wish to boot from. Accept the
settings and back out of the menu until the phone reboots itself. You
can also use the *-6-settings three finger salute to reboot your phone at
any time.

You can watch the phone pull its configuration from the TFTP server by using tshark
(yum install ethereal). Filter on port 69 using the following command:
# tshark port 69
You should then be able to watch the network traffic from the phone requesting data
from your TFTP server.
If all goes well, then you should see your phone registered to Asterisk!

Linksys SPA-942

Ever since they purchased Sipura Technologies, Linksys has been producing a line of
economical VoIP telephones and ATAs (Analog Terminal Adaptors). Linksys has been
stealing a lot of business from Cisco. If you have read Clayton M. Christensen’s
The Innovator’s Dilemma (HarperCollins), it becomes easier to understand Cisco’s
strategy with respect to Linksys.
Linksys (and Sipura) products are well regarded for their excellent quality, especially
relative to their price, but they are also famous for being painfully difficult to configure.

Configuring SIP Telephones | 95