The Asterisk Open Source PBX by Mark Spencer and the Asterisk.org developer community Copyright (C) 2001-2005 Digium, Inc. and other copyright holders. ================================================================ * SECURITY It is imperative that you read and fully understand the contents of the SECURITY file before you attempt to configure and run an Asterisk server. * WHAT IS ASTERISK ? Asterisk is an Open Source PBX and telephony toolkit. It is, in a sense, middleware between Internet and telephony channels on the bottom, and Internet and telephony applications at the top. For more information on the project itself, please visit the Asterisk home page at: http://www.asterisk.org In addition you'll find lots of information compiled by the Asterisk community on this Wiki: http://www.voip-info.org/wiki-Asterisk There is a book on Asterisk published by O'Reilly under the Creative Commons License. It is available in book stores as well as in a downloadable version on the http://www.asteriskdocs.org web site. * SUPPORTED OPERATING SYSTEMS == Linux == The Asterisk Open Source PBX is developed and tested primarily on the GNU/Linux operating system, and is supported on every major GNU/Linux distribution. == Others == Asterisk has also been 'ported' and reportedly runs properly on other operating systems as well, including Sun Solaris, Apple's Mac OS X, and the BSD variants. * GETTING STARTED First, be sure you've got supported hardware (but note that you don't need ANY special hardware, not even a soundcard) to install and run Asterisk. Supported telephony hardware includes: * All Wildcard (tm) products from Digium (www.digium.com) * QuickNet Internet PhoneJack and LineJack (http://www.quicknet.net) * any full duplex sound card supported by ALSA or OSS * VoiceTronix OpenLine products The are several drivers for ISDN BRI cards available from third party sources. Check the voip-info.org wiki for more information on chan_capi, chan_misdn and zaphfc. * UPGRADING FROM VERSION 1.0 If you are updating from a previous version of Asterisk, make sure you read the UPGRADE.txt file in the source directory. There are some files and configuration options that you will have to change, even though we made every effort possible to maintain backwards compatibility. In order to discover new features to use, please check the configuration examples in the /configs directory of the source code distribution. To discover the major new features of Asterisk 1.2, please visit http://edvina.net/asterisk1-2/ * NEW INSTALLATIONS Ensure that your system contains a compatible compiler and development libraries. Asterisk requires either the GNU Compiler Collection (GCC) version 3.0 or higher, or a compiler that supports the C99 specification and some of the gcc language extensions. In addition, your system needs to have the C library headers available, and the headers and libraries for OpenSSL, ncurses and zlib. On many distributions, these files are installed by packages with names like 'glibc-devel', 'ncurses-devel', 'openssl-devel' and 'zlib-devel' or similar. So let's proceed: 1) Run "make" Assuming the build completes successfully: 2) Run "make install" Each time you update or checkout from CVS, you are strongly encouraged to ensure all previous object files are removed to avoid internal inconsistency in Asterisk. Normally, this is automatically done with the presence of the file .cleancount, which increments each time a 'make clean' is required, and the file .lastclean, which contains the last .cleancount used. If this is your first time working with Asterisk, you may wish to install the sample PBX, with demonstration extensions, etc. If so, run: 3) "make samples" Doing so will overwrite any existing config files you have. Finally, you can launch Asterisk in the foreground mode (not a daemon) with: # asterisk -vvvc You'll see a bunch of verbose messages fly by your screen as Asterisk initializes (that's the "very very verbose" mode). When it's ready, if you specified the "c" then you'll get a command line console, that looks like this: *CLI> You can type "help" at any time to get help with the system. For help with a specific command, type "help ". To start the PBX using your sound card, you can type "dial" to dial the PBX. Then you can use "answer", "hangup", and "dial" to simulate the actions of a telephone. Remember that if you don't have a full duplex sound card (and Asterisk will tell you somewhere in its verbose messages if you do/don't) then it won't work right (not yet). "man asterisk" at the Unix/Linux command prompt will give you detailed information on how to start and stop Asterisk, as well as all the command line options for starting Asterisk. Feel free to look over the configuration files in /etc/asterisk, where you'll find a lot of information about what you can do with Asterisk. * ABOUT CONFIGURATION FILES All Asterisk configuration files share a common format. Comments are delimited by ';' (since '#' of course, being a DTMF digit, may occur in many places). A configuration file is divided into sections whose names appear in []'s. Each section typically contains two types of statements, those of the form 'variable = value', and those of the form 'object => parameters'. Internally the use of '=' and '=>' is exactly the same, so they're used only to help make the configuration file easier to understand, and do not affect how it is actually parsed. Entries of the form 'variable=value' set the value of some parameter in asterisk. For example, in zapata.conf, one might specify: switchtype=national in order to indicate to Asterisk that the switch they are connecting to is of the type "national". In general, the parameter will apply to instantiations which occur below its specification. For example, if the configuration file read: switchtype = national channel => 1-4 channel => 10-12 switchtype = dms100 channel => 25-47 the "national" switchtype would be applied to channels one through four and channels 10 through 12, whereas the "dms100" switchtype would apply to channels 25 through 47. The "object => parameters" instantiates an object with the given parameters. For example, the line "channel => 25-47" creates objects for the channels 25 through 47 of the card, obtaining the settings from the variables specified above. * SPECIAL NOTE ON TIME Those using SIP phones should be aware that Asterisk is sensitive to large jumps in time. Manually changing the system time using date(1) (or other similar commands) may cause SIP registrations and other internal processes to fail. If your system cannot keep accurate time by itself use NTP (http://www.ntp.org/) to keep the system clock synchronized to "real time". NTP is designed to keep the system clock synchronized by speeding up or slowing down the system clock until it is synchronized to "real time" rather than by jumping the time and causing discontinuities. Most Linux distributions include precompiled versions of NTP. Beware of some time synchronization methods that get the correct real time periodically and then manually set the system clock. Apparent time changes due to daylight savings time are just that, apparent. The use of daylight savings time in a Linux system is purely a user interface issue and does not affect the operation of the Linux kernel or Asterisk. The system clock on Linux kernels operates on UTC. UTC does not use daylight savings time. Also note that this issue is separate from the clocking of TDM channels, and is known to at least affect SIP registrations. * FILE DESCRIPTORS Depending on the size of your system and your configuration, Asterisk can consume a large number of file descriptors. In UNIX, file descriptors are used for more than just files on disk. File descriptors are also used for handling network communication (e.g. SIP, IAX2, or H.323 calls) and hardware access (e.g. analog and digital trunk hardware). Asterisk accesses many on-disk files for everything from configuration information to voicemail storage. Most systems limit the number of file descriptors that Asterisk can have open at one time. This can limit the number of simultaneous calls that your system can handle. For example, if the limit is set at 1024 (a common default value) Asterisk can handle approxiately 150 SIP calls simultaneously. To change the number of file descriptors follow the instructions for your system below: == PAM-based Linux System == If your system uses PAM (Pluggable Authentication Modules) edit /etc/security/limits.conf. Add these lines to the bottom of the file: root soft nofile 4096 root hard nofile 8196 asterisk soft nofile 4096 asterisk hard nofile 8196 (adjust the numbers to taste). You may need to reboot the system for these changes to take effect. == Generic UNIX System == If there are no instructions specifically adapted to your system above you can try adding the command "ulimit -n 8192" to the script that starts Asterisk. * MORE INFORMATION See the doc directory for more documentation on various features. Again, please read all the configuration samples that include documentation on the configuration options. Finally, you may wish to visit the web site and join the mailing list if you're interested in getting more information. http://www.asterisk.org/support Welcome to the growing worldwide community of Asterisk users! Mark Spencer