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Generally, the commented-out options will show you the default setting Asterisk uses,
or will tell you the default option in the option’s description.
You can also check the current state of the SIP channel in Asterisk with the sip show
settings CLI command.
If you are running Asterisk and a softphone on the same system (i.e.,
running an X-Lite softphone and Asterisk on a laptop or desktop), then
you will need to modify the SIP port that client listens on. It will need
to be changed from 5060 to 5061 (or some other unused port) so that
Asterisk and the softphone do not interfere with each other.
Essential Server Components
Before we get into how to define these files, there are a few things that need to be
configured on your server. Running the right services on your network will ensure
your Polycom sets can autoconfigure from the moment you plug them in. There’s a
little work involved here, but we promise that the payoff is worth it. Once you’ve done
this a few times, it only really takes a few minutes on each new system, and going
forward, it’ll save you a lot of mucking about with web interfaces. When you take your
new Polycom phone out of the box, plug it into your network, watch it autoconfigure
itself, and then successfully register with your Asterisk machine, you will know the sort
of joy that only geeks can experience. *
It’s not really that complicated. Where we think people get confused is in making sense
of the various ways this can be achieved, because there are a lot of choices.
DHCP server
Typically, a DHCP server is used to configure basic IP parameters for a device (IP ad-
dress, default gateway, and DNS), but the DHCP protocol can actually pass many other
parameters. In our case, we want it to pass some information to the sets that will tell
them where to download their config files from. Here is a sample config from a Linux
DHCP server that will do what is required:
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 ntp-servers pool.ntp.org;
* Typically, it’s at 4 A.M. on the morning of a critical 8 A.M. meeting, after having worked all weekend. Red
Bull is probably the most popular drink of the Asterisk developers. Dr. Pepper would be a close second. Red
Bull, anyone?
Configuring SIP Telephones | 85