Switching to VoIP

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Compiling and Installing Asterisk

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45

Starting and Stopping the Asterisk Server

The Asterisk binary is the program that you execute whenever you want to start the

Asterisk server or connect to it for management purposes. The same program has

two distinct modes of operation—server mode and client mode. The server is the

instance of Asterisk that stays running all the time, handling calls, recording voice

mail, greeting callers while users are away, and so on. The client is the instance of

Asterisk that allows you to monitor and manipulate the server while it runs. The

mode the program uses depends on how Asterisk is invoked at the command prompt

or within a shell script.

To launch Asterisk in server mode, execute this command:

# asterisk &

To connect Asterisk in client mode on a machine already running in server mode,

execute this command:

# asterisk –r

Once the Asterisk client is connected to the Asterisk server, you can use Asterisk’s

command-line interface to issues queries and commands about the telephony server.

These include listing calls-in-progress, listing used and unused channels, and stop-

ping the Asterisk server.

Several Asterisk CLI commands shut down the server:

•

restart now

• restart when convenient

• stop now

• stop when convenient

The restart commands stop and then restart the Asterisk server process, which can

be helpful in situations where the server’s configuration has significantly changed

and needs to be restarted. The

stop commands just shut the Asterisk server process

down. You’ll have to execute the Asterisk program to get it running again.

The

now and when convenient arguments tell Asterisk how quickly to shut down or

restart. If you want to ignore the current calls and tasks in progress on the server,

now

is appropriate. If you want Asterisk to wait until all the calls and tasks are finished

and there is no call activity at all,

when convenient is appropriate. Generally, espe-

cially if you’re planning to have any callers beside yourself on the system, get in the

habit of using

when convenient.

Of course, in extreme circumstances, like if the Asterisk CLI is unavailable or not

responsive, you can stop the Asterisk server process from a shell like this. Get the

process ID (PID) of the Asterisk server process:

# ps ax | grep asterisk