Thu Oct 11 06:44:30 2012

Asterisk developer's documentation


IAX2 configuration

IAX2 is implemented in chan_iax2.c

IAX readme file

Inter-Asterisk eXchange Protocol
================================

Usage:
======
The format for the dialing string on Asterisk is:
IAX/[user@]peer[:exten[@context]]

(Note, []'s denote optional fields).  The peer is either an IP address
or a peer as specified in the /etc/asterisk/iax.conf file.  Exten is
an optional requested extension (otherwise "s" will be used), and 
"context" is an optional context to request.  The user is an optional
username specified in the peer's iax.conf.  If the user is not specified,
the peer will select one.

The peer uses a score to determine the best user entry to match against if
one is not specified:

1. User entry with secret and no ACL specified.
2. User entry with secret specified and ACL specified.
3. User entry with no secret specified and no ACL specified.
4. User entry with no secret specified and ACL specified.
5. User entry matched via username.

The higher the score the better it is with 5 being an exact match and the maximum
score possible.

Protocol and rationale:
=======================
IAX is a simple, low overhead and low bandwidth VoIP protocol designed to 
allow multiple Asterisk PBX's to communicate with one another without
the overhead of more complex protocols like H.323.  Payload is sent with
a header overhead of only 4 octets.  Control functions (and one payload packet
per minute or so) is sent with a more complex header of 12 octets.

IAX is slightly stateful.

IAX contains two kinds of packets:  The full header packet type, which 
contains much information about the frame, in addition to its contents,
and the mini header type, which is used only for non-reliable voice
packet delivery.

All packets are immediately transmitted.  Packets are received, but not
delivered to the actual channels until a given time quantum has passed, in
order to try to eliminate jitter.

All full header packets must be ackd (except, obviously for the ACK packets
themselves and not so obviously for hangup packets).  The "timestamp" field of
ack packets is not the normal offset, but rather a quote of the timestamp as
included with the original packet that you're acking, and likewise the
seqno field is the seqno of the packet you're acking, not your own seqno,
and you do not increment your own sequence number.  ACKing is based on the
sequence number.

See iax.h for a description of the frame formats. 

IAX internal frames use the AST_FRAME_IAX type.  The subclass of these
frames is the IAX control number, as seen in iax.h.  The first frame sent
must be an AST_FRAME_IAX with the control AST_IAX_CONTROL_NEW.  

The AST_IAX_CONTROL_NEW establishes a new connection.  

The first frame sent MUST be an AST_CONTROL_NEW to start a connection.

IAX connnections may require authentication using either simple plaintext
passwords or an md5 challenge/response pair.

IAX2 configuration

; Inter-Asterisk eXchange driver definition
;
; This configuration is re-read at reload
; or with the CLI command
; 	reload chan_iax2.so
;
; General settings, like port number to bind to, and
; an option address (the default is to bind to all
; local addresses).
;
[general]
;bindport=4569			; bindport and bindaddr may be specified
;                               ; NOTE: bindport must be specified BEFORE
				; bindaddr or may be specified on a specific
				; bindaddr if followed by colon and port
				;  (e.g. bindaddr=192.168.0.1:4569)
;bindaddr=192.168.0.1		; more than once to bind to multiple
;                               ; addresses, but the first will be the 
;                               ; default
;
; Set iaxcompat to yes if you plan to use layered switches or
; some other scenario which may cause some delay when doing a
; lookup in the dialplan. It incurs a small performance hit to
; enable it. This option causes Asterisk to spawn a separate thread
; when it receives an IAX DPREQ (Dialplan Request) instead of
; blocking while it waits for a response.
;
;iaxcompat=yes
;
; Disable UDP checksums (if nochecksums is set, then no checkums will
; be calculated/checked on systems supporting this feature)
;
;nochecksums=no
;
;
; For increased security against brute force password attacks
; enable "delayreject" which will delay the sending of authentication
; reject for REGREQ or AUTHREP if there is a password.  
;
;delayreject=yes
;
; You may specify a global default AMA flag for iaxtel calls.  It must be
; one of 'default', 'omit', 'billing', or 'documentation'.  These flags
; are used in the generation of call detail records.
;
;amaflags=default
;
; ADSI (Analog Display Services Interface) can be enabled if you have
; (or may have) ADSI compatible CPE equipment
;
;adsi=no
;
; You may specify a default account for Call Detail Records in addition
; to specifying on a per-user basis
;
;accountcode=lss0101
;
; You may specify a global default language for users. 
; Can be specified also on a per-user basis
; If omitted, will fallback to english
;
;language=en
;
; This option specifies a preference for which music on hold class this channel
; should listen to when put on hold if the music class has not been set on the
; channel with Set(CHANNEL(musicclass)=whatever) in the dialplan, and the peer
; channel putting this one on hold did not suggest a music class.
;
; If this option is set to "passthrough", then the hold message will always be
; passed through as signalling instead of generating hold music locally.
;
; This option may be specified globally, or on a per-user or per-peer basis.
;
;mohinterpret=default
;
; This option specifies which music on hold class to suggest to the peer channel
; when this channel places the peer on hold. It may be specified globally or on
; a per-user or per-peer basis.
;
;mohsuggest=default
;
; Specify bandwidth of low, medium, or high to control which codecs are used
; in general.
;
bandwidth=low
;
; You can also fine tune codecs here using "allow" and "disallow" clauses
; with specific codecs.  Use "all" to represent all formats.
;
;allow=all			; same as bandwidth=high
;disallow=g723.1		; Hm...  Proprietary, don't use it...
disallow=lpc10			; Icky sound quality...  Mr. Roboto.
;allow=gsm			; Always allow GSM, it's cool :)
;

; You can adjust several parameters relating to the jitter buffer.
; The jitter buffer's function is to compensate for varying
; network delay.
;
; All the jitter buffer settings are in milliseconds.
; The jitter buffer works for INCOMING audio - the outbound audio
; will be dejittered by the jitter buffer at the other end.
;
; jitterbuffer=yes|no: global default as to whether you want
; the jitter buffer at all.
;
; forcejitterbuffer=yes|no: in the ideal world, when we bridge VoIP channels
; we don't want to do jitterbuffering on the switch, since the endpoints
; can each handle this.  However, some endpoints may have poor jitterbuffers 
; themselves, so this option will force * to always jitterbuffer, even in this
; case.
;
; maxjitterbuffer: a maximum size for the jitter buffer.
; Setting a reasonable maximum here will prevent the call delay
; from rising to silly values in extreme situations; you'll hear
; SOMETHING, even though it will be jittery.
;
; resyncthreshold: when the jitterbuffer notices a significant change in delay
; that continues over a few frames, it will resync, assuming that the change in
; delay was caused by a timestamping mix-up. The threshold for noticing a
; change in delay is measured as twice the measured jitter plus this resync
; threshold.
; Resyncing can be disabled by setting this parameter to -1.
;
; maxjitterinterps: the maximum number of interpolation frames the jitterbuffer
; should return in a row. Since some clients do not send CNG/DTX frames to
; indicate silence, the jitterbuffer will assume silence has begun after
; returning this many interpolations. This prevents interpolating throughout
; a long silence.
;

jitterbuffer=no
forcejitterbuffer=no
;maxjitterbuffer=1000
;maxjitterinterps=10
;resyncthreshold=1000

;trunkfreq=20			; How frequently to send trunk msgs (in ms)

; Should we send timestamps for the individual sub-frames within trunk frames?
; There is a small bandwidth use for these (less than 1kbps/call), but they
; ensure that frame timestamps get sent end-to-end properly.  If both ends of
; all your trunks go directly to TDM, _and_ your trunkfreq equals the frame
; length for your codecs, you can probably suppress these.  The receiver must
; also support this feature, although they do not also need to have it enabled.
;
; trunktimestamps=yes
;
; Minimum and maximum amounts of time that IAX peers can request as
; a registration expiration interval (in seconds).
; minregexpire = 60
; maxregexpire = 60
;
; IAX helper threads
; Establishes the number of iax helper threads to handle I/O.
; iaxthreadcount = 10
; Establishes the number of extra dynamic threads that may be spawned to handle I/O
; iaxmaxthreadcount = 100
;
; We can register with another IAX server to let him know where we are
; in case we have a dynamic IP address for example
;
; Register with tormenta using username marko and password secretpass
;
;register => marko:secretpass@tormenta.linux-support.net
;
; Register joe at remote host with no password
;
;register => joe@remotehost:5656
;
; Register marko at tormenta.linux-support.net using RSA key "torkey"
;
;register => marko:[torkey]@tormenta.linux-support.net
;
; Sample Registration for iaxtel
;
; Visit http://www.iaxtel.com to register with iaxtel.  Replace "user"
; and "pass" with your username and password for iaxtel.  Incoming 
; calls arrive at the "s" extension of "default" context.
;
;register => user:pass@iaxtel.com
;
; Sample Registration for IAX + FWD
;
; To register using IAX with FWD, it must be enabled by visiting the URL
; http://www.fwdnet.net/index.php?section_id=112
;
; Note that you need an extension in you default context which matches
; your free world dialup number.  Please replace "FWDNumber" with your
; FWD number and "passwd" with your password.
;
;register => FWDNumber:passwd@iax.fwdnet.net
;
;
; You can disable authentication debugging to reduce the amount of 
; debugging traffic.
;
;authdebug=no
;
; See doc/ip-tos.txt for a description of the tos parameters.
;tos=ef
;
; If regcontext is specified, Asterisk will dynamically create and destroy
; a NoOp priority 1 extension for a given peer who registers or unregisters
; with us.  The actual extension is the 'regexten' parameter of the registering
; peer or its name if 'regexten' is not provided.  More than one regexten
; may be supplied if they are separated by '&'.  Patterns may be used in
; regexten.
;
;regcontext=iaxregistrations
;
; If we don't get ACK to our NEW within 2000ms, and autokill is set to yes,
; then we cancel the whole thing (that's enough time for one retransmission
; only).  This is used to keep things from stalling for a long time for a host
; that is not available, but would be ill advised for bad connections.  In
; addition to 'yes' or 'no' you can also specify a number of milliseconds.
; See 'qualify' for individual peers to turn on for just a specific peer.
;
autokill=yes
;
; codecpriority controls the codec negotiation of an inbound IAX call.
; This option is inherited to all user entities.  It can also be defined 
; in each user entity separately which will override the setting in general.
;
; The valid values are:
;
; caller   - Consider the callers preferred order ahead of the host's.
; host     - Consider the host's preferred order ahead of the caller's.
; disabled - Disable the consideration of codec preference altogether.
;            (this is the original behaviour before preferences were added)
; reqonly  - Same as disabled, only do not consider capabilities if
;            the requested format is not available the call will only
;            be accepted if the requested format is available.
;
; The default value is 'host'
;
;codecpriority=host
;
; allowfwdownload controls whether this host will serve out firmware to
; IAX clients which request it.  This has only been used for the IAXy,
; and it has been recently proven that this firmware distribution method
; can be used as a source of traffic amplification attacks.  Also, the
; IAXy firmware has not been updated for at least 18 months, so unless
; you are provisioning IAXys in a secure network, we recommend that you
; leave this option to the default, off.
;
;allowfwdownload=yes

;rtcachefriends=yes	; Cache realtime friends by adding them to the internal list
			; just like friends added from the config file only on a
			; as-needed basis? (yes|no)

;rtupdate=yes		; Send registry updates to database using realtime? (yes|no)
			; If set to yes, when a IAX2 peer registers successfully,
			; the ip address, the origination port, the registration period,
			; and the username of the peer will be set to database via realtime.
			; If not present, defaults to 'yes'.

;rtautoclear=yes	; Auto-Expire friends created on the fly on the same schedule
			; as if it had just registered? (yes|no|<seconds>)
			; If set to yes, when the registration expires, the friend will
			; vanish from the configuration until requested again.
			; If set to an integer, friends expire within this number of
			; seconds instead of the registration interval.

;rtignoreregexpire=yes	; When reading a peer from Realtime, if the peer's registration
			; has expired based on its registration interval, used the stored
			; address information regardless. (yes|no)

;
; The following two options are used to disable call token validation for the
; purposes of interoperability with IAX2 endpoints that do not yet support it.
;
; Call token validation can be set as optional for a single IP address or IP
; address range by using the 'calltokenoptional' option. 'calltokenoptional' is
; only a global option.  
;
;calltokenoptional=209.16.236.73/255.255.255.0
;
; By setting 'requirecalltoken=no', call token validation becomes optional for
; that peer/user.  By setting 'requirecalltoken=auto', call token validation 
; is optional until a call token supporting peer registers successfully using
; call token validation.  This is used as an indication that from now on, we
; can require it from this peer.  So, requirecalltoken is internally set to yes.
; requirecalltoken may only be used in peer/user/friend definitions,
; not in the global scope.
; By default, 'requirecalltoken=yes'.
;
;requirecalltoken=no
;

;
; These options are used to limit the amount of call numbers allocated to a
; single IP address.  Before changing any of these values, it is highly encouraged
; to read the user guide associated with these options first.  In most cases, the
; default values for these options are sufficient.
;
; The 'maxcallnumbers' option limits the amount of call numbers allowed for each
; individual remote IP address.  Once an IP address reaches it's call number
; limit, no more new connections are allowed until the previous ones close.  This
; option can be used in a peer definition as well, but only takes effect for
; the IP of a dynamic peer after it completes registration.
;
;maxcallnumbers=512
;
; The 'maxcallnumbers_nonvalidated' is used to set the combined number of call
; numbers that can be allocated for connections where call token  validation
; has been disabled.  Unlike the 'maxcallnumbers' option, this limit is not
; separate for each individual IP address.  Any connection resulting in a
; non-call token validated call number being allocated contributes to this
; limit.  For use cases, see the call token user guide.  This option's 
; default value of 8192 should be sufficient in most cases.
;
;maxcallnumbers_nonvalidated=1024
;
; The [callnumberlimits] section allows custom call number limits to be set
; for specific IP addresses and IP address ranges.  These limits take precedence
; over the global 'maxcallnumbers' option, but may still be overridden by a
; peer defined 'maxcallnumbers' entry.  Note that these limits take effect
; for every individual address within the range, not the range as a whole. 
;
;[callnumberlimits]
;10.1.1.0/255.255.255.0 = 24
;10.1.2.0/255.255.255.0 = 32
;

; The shrinkcallerid function removes '(', ' ', ')', non-trailing '.', and '-' not
; in square brackets.  For example, the caller id value 555.5555 becomes 5555555
; when this option is enabled.  Disabling this option results in no modification
; of the caller id value, which is necessary when the caller id represents something
; that must be preserved.  This option can only be used in the [general] section.
; By default this option is on.
;
;shrinkcallerid=yes     ; on by default

; Guest sections for unauthenticated connection attempts.  Just specify an
; empty secret, or provide no secret section.
;
[guest]
type=user
context=default
callerid="Guest IAX User"

;
; Trust Caller*ID Coming from iaxtel.com
;
[iaxtel]
type=user
context=default
auth=rsa
inkeys=iaxtel

;
; Trust Caller*ID Coming from iax.fwdnet.net
;
[iaxfwd]
type=user
context=default
auth=rsa
inkeys=freeworlddialup

;
; Trust callerid delivered over DUNDi/e164
;
;
;[dundi]
;type=user
;dbsecret=dundi/secret
;context=dundi-e164-local

;
; Further user sections may be added, specifying a context and a secret used
; for connections with that given authentication name.  Limited IP based
; access control is allowed by use of "permit" and "deny" keywords.  Multiple
; rules are permitted.  Multiple permitted contexts may be specified, in
; which case the first will be the default.  You can also override caller*ID
; so that when you receive a call you set the Caller*ID to be what you want
; instead of trusting what the remote user provides
;
; There are three authentication methods that are supported:  md5, plaintext,
; and rsa.  The least secure is "plaintext", which sends passwords cleartext
; across the net.  "md5" uses a challenge/response md5 sum arrangement, but
; still requires both ends have plain text access to the secret.  "rsa" allows
; unidirectional secret knowledge through public/private keys.  If "rsa"
; authentication is used, "inkeys" is a list of acceptable public keys on the 
; local system that can be used to authenticate the remote peer, separated by
; the ":" character.  "outkey" is a single, private key to use to authenticate
; to the other side.  Public keys are named /var/lib/asterisk/keys/<name>.pub
; while private keys are named /var/lib/asterisk/keys/<name>.key.  Private
; keys should always be 3DES encrypted.
;
;
; NOTE: All hostnames and IP addresses in this file are for example purposes
;       only; you should not expect any of them to actually be available for
;       your use.
;
;
;[markster]
;type=user
;context=default
;context=local
;auth=md5,plaintext,rsa
;secret=markpasswd
;setvar=foo=bar
;dbsecret=mysecrets/place	; Secrets can be stored in astdb, too
;transfer=no		; Disable IAX native transfer
;transfer=mediaonly	; When doing IAX native transfers, transfer 
			; only media stream
;jitterbuffer=yes	; Override global setting an enable jitter buffer
;			; for this user
;maxauthreq=10          ; Set maximum number of outstanding AUTHREQs waiting for replies. Any further authentication attempts will be blocked
;                       ; if this limit is reached until they expire or a reply is received.
;callerid="Mark Spencer" <(256) 428-6275>
;deny=0.0.0.0/0.0.0.0
;accountcode=markster0101
;permit=209.16.236.73/255.255.255.0
;language=en		; Use english as default language
;
; Peers may also be specified, with a secret and
; a remote hostname.
;
[demo]
type=peer
username=asterisk
secret=supersecret
host=216.207.245.47
;sendani=no
;host=asterisk.linux-support.net
;port=5036
;mask=255.255.255.255
;qualify=yes			; Make sure this peer is alive
;qualifysmoothing = yes		; use an average of the last two PONG
				; results to reduce falsely detected LAGGED hosts
				; Default: Off
;qualifyfreqok = 60000		; how frequently to ping the peer when
				; everything seems to be ok, in milliseconds
;qualifyfreqnotok = 10000	; how frequently to ping the peer when it's
				; either LAGGED or UNAVAILABLE, in milliseconds
;jitterbuffer=no		; Turn off jitter buffer for this peer

;
; Peers can remotely register as well, so that they can be mobile.  Default
; IP's can also optionally be given but are not required.  Caller*ID can be
; suggested to the other side as well if it is for example a phone instead of
; another PBX.
;

;[dynamichost]
;host=dynamic
;secret=mysecret
;mailbox=1234		; Notify about mailbox 1234
;inkeys=key1:key2
;peercontext=local	; Default context to request for calls to peer
;defaultip=216.207.245.34
;callerid="Some Host" <(256) 428-6011>
;

;
;[biggateway]
;type=peer
;host=192.168.0.1
;context=*
;secret=myscret
;trunk=yes			; Use IAX2 trunking with this host
;timezone=America/New_York	; Set a timezone for the date/time IE
;

;
; Friends are a short cut for creating a user and
; a peer with the same values.
;
;[marko]
;type=friend
;host=dynamic
;regexten=1234
;secret=moofoo   ; Multiple secrets may be specified. For a "user", all
;secret=foomoo   ; specified entries will be accepted as valid. For a "peer",
;secret=shazbot  ; only the last specified secret will be used.
;context=default
;permit=0.0.0.0/0.0.0.0

IAX Jitterbuffer information

The new Jitterbuffer in Asterisk
--------------------------------
Steve Kann



The new jitterbuffer, PLC, and the IAX2-integration of the new jitterbuffer 
have been integrated into Asterisk. The jitterbuffer is generic and work is 
going on to implement it in SIP/RTP as well.

Also, we've added a feature called "trunktimestamps", which adds individual 
timestamps to trunked frames within a trunk frame.

Here's how to use this stuff:

1) The new jitterbuffer:  
------------------------
You must add "jitterbuffer=yes" to either the [general] part of 
iax.conf, or to a peer or a user.  (just like the old jitterbuffer).    
Also, you can set "maxjitterbuffer=n", which puts a hard-limit on the size of the 
jitterbuffer of "n milliseconds".  It is not necessary to have the new jitterbuffer 
on both sides of a call; it works on the receive side only.

2) PLC:
-------  
The new jitterbuffer detects packet loss.  PLC is done to try to recreate these
lost packets in the codec decoding stage, as the encoded audio is translated to slinear.  
PLC is also used to mask jitterbuffer growth.

This facility is enabled by default in iLBC and speex, as it has no additional cost.
This facility can be enabled in adpcm, alaw, g726, gsm, lpc10, and ulaw by setting 
genericplc => true in the [plc] section of codecs.conf.

3) Trunktimestamps:
-------------------
To use this, both sides must be using Asterisk v1.2.
Setting "trunktimestamps=yes" in iax.conf will cause your box to send 16-bit timestamps 
for each trunked frame inside of a trunk frame. This will enable you to use jitterbuffer
for an IAX2 trunk, something that was not possible in the old architecture.

The other side must also support this functionality, or else, well, bad things will happen.  
If you don't use trunktimestamps, there's lots of ways the jitterbuffer can get confused because 
timestamps aren't necessarily sent through the trunk correctly.

4) Communication with Asterisk v1.0.x systems
---------------------------------------------
You can set up communication with v1.0.x systems with the new jitterbuffer, but
you can't use trunks with trunktimestamps in this communication.

If you are connecting to an Asterisk server with earlier versions of the software (1.0.x),
do not enable both jitterbuffer and trunking for the involved peers/users 
in order to be able  to communicate. Earlier systems will not support trunktimestamps.

You may also compile chan_iax2.c without the new jitterbuffer, enabling the old 
backwards compatible architecture. Look in the source code for instructions.


5) Testing and monitoring:
--------------------------
You can test the effectiveness of PLC and the new jitterbuffer's detection of loss by using 
the new CLI command "iax2 test losspct <n>".  This will simulate n percent packet loss 
coming _in_ to chan_iax2. You should find that with PLC and the new JB, 10 percent packet 
loss should lead to just a tiny amount of distortion, while without PLC, it would lead to 
silent gaps in your audio.

"iax2 show netstats" shows you statistics for each iax2 call you have up.  
The columns are "RTT" which is the round-trip time for the last PING, and then a bunch of s
tats for both the local side (what you're receiving), and the remote side (what the other 
end is telling us they are seeing).  The remote stats may not be complete if the remote 
end isn't using the new jitterbuffer.

The stats shown are:
* Jit: The jitter we have measured (milliseconds)
* Del: The maximum delay imposed by the jitterbuffer (milliseconds)
* Lost: The number of packets we've detected as lost.
* %: The percentage of packets we've detected as lost recently.
* Drop: The number of packets we've purposely dropped (to lower latency).
* OOO: The number of packets we've received out-of-order
* Kpkts: The number of packets we've received / 1000.

Reporting problems 
==================

There's a couple of things that can make calls sound bad using the jitterbuffer:

1) The JB and PLC can make your calls sound better, but they can't fix everything.  
If you lost 10 frames in a row, it can't possibly fix that.  It really can't help much 
more than one or two consecutive frames.

2) Bad timestamps:  If whatever is generating timestamps to be sent to you generates 
nonsensical timestamps, it can confuse the jitterbuffer.  In particular, discontinuities 
in timestamps will really upset it:  Things like timestamps sequences which go 0, 20, 40, 
60, 80,  34000, 34020, 34040, 34060...   It's going to think you've got about 34 seconds 
of jitter in this case, etc..
The right solution to this is to find out what's causing the sender to send us such nonsense, 
and fix that.  But we should also figure out how to make the receiver more robust in 
cases like this.

chan_iax2 will actually help fix this a bit if it's more than 3 seconds or so, but at 
some point we should try to think of a better way to detect this kind of thing and 
resynchronize.

Different clock rates are handled very gracefully though; it will actually deal with a 
sender sending 20% faster or slower than you expect just fine.

3) Really strange network delays:  If your network "pauses" for like 5 seconds, and then 
when it restarts, you are sent some packets that are 5 seconds old, we are going to see 
that as a lot of jitter.   We already throw away up to the worst 20 frames like this, 
though, and the "maxjitterbuffer" parameter should put a limit on what we do in this case.

Reporting possible bugs
-----------------------
If you do find bad behaviors, here's the information that will help to diagnose this:

1) Describe

a) the source of the timestamps and frames:  i.e. if they're coming from another chan_iax2 box, 
a bridged RTP-based channel, an IAX2 softphone, etc..

b) The network between, in brief (i.e. the internet, a local lan, etc).

c) What is the problem you're seeing.


2) Take a look and see what iax2 show netstats is saying about the call, and if it makes sense.

3) a tcpdump of the frames, (or, tethereal output from), so we can see the timestamps and delivery 
times of the frames you're receiving.  You can make such a tcpdump with:

tcpdump -s 2048 -w /tmp/example.dump udp and port 4569 [and host <other-end>]

Report bugs in the Asterisk bugtracker, http://bugs.digium.com.
Please read the bug guidelines before you post a bug.

Have fun!

-SteveK

iax.conf

; Inter-Asterisk eXchange driver definition
;
; This configuration is re-read at reload
; or with the CLI command
; 	reload chan_iax2.so
;
; General settings, like port number to bind to, and
; an option address (the default is to bind to all
; local addresses).
;
[general]
;bindport=4569			; bindport and bindaddr may be specified
;                               ; NOTE: bindport must be specified BEFORE
				; bindaddr or may be specified on a specific
				; bindaddr if followed by colon and port
				;  (e.g. bindaddr=192.168.0.1:4569)
;bindaddr=192.168.0.1		; more than once to bind to multiple
;                               ; addresses, but the first will be the 
;                               ; default
;
; Set iaxcompat to yes if you plan to use layered switches or
; some other scenario which may cause some delay when doing a
; lookup in the dialplan. It incurs a small performance hit to
; enable it. This option causes Asterisk to spawn a separate thread
; when it receives an IAX DPREQ (Dialplan Request) instead of
; blocking while it waits for a response.
;
;iaxcompat=yes
;
; Disable UDP checksums (if nochecksums is set, then no checkums will
; be calculated/checked on systems supporting this feature)
;
;nochecksums=no
;
;
; For increased security against brute force password attacks
; enable "delayreject" which will delay the sending of authentication
; reject for REGREQ or AUTHREP if there is a password.  
;
;delayreject=yes
;
; You may specify a global default AMA flag for iaxtel calls.  It must be
; one of 'default', 'omit', 'billing', or 'documentation'.  These flags
; are used in the generation of call detail records.
;
;amaflags=default
;
; ADSI (Analog Display Services Interface) can be enabled if you have
; (or may have) ADSI compatible CPE equipment
;
;adsi=no
;
; You may specify a default account for Call Detail Records in addition
; to specifying on a per-user basis
;
;accountcode=lss0101
;
; You may specify a global default language for users. 
; Can be specified also on a per-user basis
; If omitted, will fallback to english
;
;language=en
;
; This option specifies a preference for which music on hold class this channel
; should listen to when put on hold if the music class has not been set on the
; channel with Set(CHANNEL(musicclass)=whatever) in the dialplan, and the peer
; channel putting this one on hold did not suggest a music class.
;
; If this option is set to "passthrough", then the hold message will always be
; passed through as signalling instead of generating hold music locally.
;
; This option may be specified globally, or on a per-user or per-peer basis.
;
;mohinterpret=default
;
; This option specifies which music on hold class to suggest to the peer channel
; when this channel places the peer on hold. It may be specified globally or on
; a per-user or per-peer basis.
;
;mohsuggest=default
;
; Specify bandwidth of low, medium, or high to control which codecs are used
; in general.
;
bandwidth=low
;
; You can also fine tune codecs here using "allow" and "disallow" clauses
; with specific codecs.  Use "all" to represent all formats.
;
;allow=all			; same as bandwidth=high
;disallow=g723.1		; Hm...  Proprietary, don't use it...
disallow=lpc10			; Icky sound quality...  Mr. Roboto.
;allow=gsm			; Always allow GSM, it's cool :)
;

; You can adjust several parameters relating to the jitter buffer.
; The jitter buffer's function is to compensate for varying
; network delay.
;
; All the jitter buffer settings are in milliseconds.
; The jitter buffer works for INCOMING audio - the outbound audio
; will be dejittered by the jitter buffer at the other end.
;
; jitterbuffer=yes|no: global default as to whether you want
; the jitter buffer at all.
;
; forcejitterbuffer=yes|no: in the ideal world, when we bridge VoIP channels
; we don't want to do jitterbuffering on the switch, since the endpoints
; can each handle this.  However, some endpoints may have poor jitterbuffers 
; themselves, so this option will force * to always jitterbuffer, even in this
; case.
;
; maxjitterbuffer: a maximum size for the jitter buffer.
; Setting a reasonable maximum here will prevent the call delay
; from rising to silly values in extreme situations; you'll hear
; SOMETHING, even though it will be jittery.
;
; resyncthreshold: when the jitterbuffer notices a significant change in delay
; that continues over a few frames, it will resync, assuming that the change in
; delay was caused by a timestamping mix-up. The threshold for noticing a
; change in delay is measured as twice the measured jitter plus this resync
; threshold.
; Resyncing can be disabled by setting this parameter to -1.
;
; maxjitterinterps: the maximum number of interpolation frames the jitterbuffer
; should return in a row. Since some clients do not send CNG/DTX frames to
; indicate silence, the jitterbuffer will assume silence has begun after
; returning this many interpolations. This prevents interpolating throughout
; a long silence.
;

jitterbuffer=no
forcejitterbuffer=no
;maxjitterbuffer=1000
;maxjitterinterps=10
;resyncthreshold=1000

;trunkfreq=20			; How frequently to send trunk msgs (in ms)

; Should we send timestamps for the individual sub-frames within trunk frames?
; There is a small bandwidth use for these (less than 1kbps/call), but they
; ensure that frame timestamps get sent end-to-end properly.  If both ends of
; all your trunks go directly to TDM, _and_ your trunkfreq equals the frame
; length for your codecs, you can probably suppress these.  The receiver must
; also support this feature, although they do not also need to have it enabled.
;
; trunktimestamps=yes
;
; Minimum and maximum amounts of time that IAX peers can request as
; a registration expiration interval (in seconds).
; minregexpire = 60
; maxregexpire = 60
;
; IAX helper threads
; Establishes the number of iax helper threads to handle I/O.
; iaxthreadcount = 10
; Establishes the number of extra dynamic threads that may be spawned to handle I/O
; iaxmaxthreadcount = 100
;
; We can register with another IAX server to let him know where we are
; in case we have a dynamic IP address for example
;
; Register with tormenta using username marko and password secretpass
;
;register => marko:secretpass@tormenta.linux-support.net
;
; Register joe at remote host with no password
;
;register => joe@remotehost:5656
;
; Register marko at tormenta.linux-support.net using RSA key "torkey"
;
;register => marko:[torkey]@tormenta.linux-support.net
;
; Sample Registration for iaxtel
;
; Visit http://www.iaxtel.com to register with iaxtel.  Replace "user"
; and "pass" with your username and password for iaxtel.  Incoming 
; calls arrive at the "s" extension of "default" context.
;
;register => user:pass@iaxtel.com
;
; Sample Registration for IAX + FWD
;
; To register using IAX with FWD, it must be enabled by visiting the URL
; http://www.fwdnet.net/index.php?section_id=112
;
; Note that you need an extension in you default context which matches
; your free world dialup number.  Please replace "FWDNumber" with your
; FWD number and "passwd" with your password.
;
;register => FWDNumber:passwd@iax.fwdnet.net
;
;
; You can disable authentication debugging to reduce the amount of 
; debugging traffic.
;
;authdebug=no
;
; See doc/ip-tos.txt for a description of the tos parameters.
;tos=ef
;
; If regcontext is specified, Asterisk will dynamically create and destroy
; a NoOp priority 1 extension for a given peer who registers or unregisters
; with us.  The actual extension is the 'regexten' parameter of the registering
; peer or its name if 'regexten' is not provided.  More than one regexten
; may be supplied if they are separated by '&'.  Patterns may be used in
; regexten.
;
;regcontext=iaxregistrations
;
; If we don't get ACK to our NEW within 2000ms, and autokill is set to yes,
; then we cancel the whole thing (that's enough time for one retransmission
; only).  This is used to keep things from stalling for a long time for a host
; that is not available, but would be ill advised for bad connections.  In
; addition to 'yes' or 'no' you can also specify a number of milliseconds.
; See 'qualify' for individual peers to turn on for just a specific peer.
;
autokill=yes
;
; codecpriority controls the codec negotiation of an inbound IAX call.
; This option is inherited to all user entities.  It can also be defined 
; in each user entity separately which will override the setting in general.
;
; The valid values are:
;
; caller   - Consider the callers preferred order ahead of the host's.
; host     - Consider the host's preferred order ahead of the caller's.
; disabled - Disable the consideration of codec preference altogether.
;            (this is the original behaviour before preferences were added)
; reqonly  - Same as disabled, only do not consider capabilities if
;            the requested format is not available the call will only
;            be accepted if the requested format is available.
;
; The default value is 'host'
;
;codecpriority=host
;
; allowfwdownload controls whether this host will serve out firmware to
; IAX clients which request it.  This has only been used for the IAXy,
; and it has been recently proven that this firmware distribution method
; can be used as a source of traffic amplification attacks.  Also, the
; IAXy firmware has not been updated for at least 18 months, so unless
; you are provisioning IAXys in a secure network, we recommend that you
; leave this option to the default, off.
;
;allowfwdownload=yes

;rtcachefriends=yes	; Cache realtime friends by adding them to the internal list
			; just like friends added from the config file only on a
			; as-needed basis? (yes|no)

;rtupdate=yes		; Send registry updates to database using realtime? (yes|no)
			; If set to yes, when a IAX2 peer registers successfully,
			; the ip address, the origination port, the registration period,
			; and the username of the peer will be set to database via realtime.
			; If not present, defaults to 'yes'.

;rtautoclear=yes	; Auto-Expire friends created on the fly on the same schedule
			; as if it had just registered? (yes|no|<seconds>)
			; If set to yes, when the registration expires, the friend will
			; vanish from the configuration until requested again.
			; If set to an integer, friends expire within this number of
			; seconds instead of the registration interval.

;rtignoreregexpire=yes	; When reading a peer from Realtime, if the peer's registration
			; has expired based on its registration interval, used the stored
			; address information regardless. (yes|no)

;
; The following two options are used to disable call token validation for the
; purposes of interoperability with IAX2 endpoints that do not yet support it.
;
; Call token validation can be set as optional for a single IP address or IP
; address range by using the 'calltokenoptional' option. 'calltokenoptional' is
; only a global option.  
;
;calltokenoptional=209.16.236.73/255.255.255.0
;
; By setting 'requirecalltoken=no', call token validation becomes optional for
; that peer/user.  By setting 'requirecalltoken=auto', call token validation 
; is optional until a call token supporting peer registers successfully using
; call token validation.  This is used as an indication that from now on, we
; can require it from this peer.  So, requirecalltoken is internally set to yes.
; requirecalltoken may only be used in peer/user/friend definitions,
; not in the global scope.
; By default, 'requirecalltoken=yes'.
;
;requirecalltoken=no
;

;
; These options are used to limit the amount of call numbers allocated to a
; single IP address.  Before changing any of these values, it is highly encouraged
; to read the user guide associated with these options first.  In most cases, the
; default values for these options are sufficient.
;
; The 'maxcallnumbers' option limits the amount of call numbers allowed for each
; individual remote IP address.  Once an IP address reaches it's call number
; limit, no more new connections are allowed until the previous ones close.  This
; option can be used in a peer definition as well, but only takes effect for
; the IP of a dynamic peer after it completes registration.
;
;maxcallnumbers=512
;
; The 'maxcallnumbers_nonvalidated' is used to set the combined number of call
; numbers that can be allocated for connections where call token  validation
; has been disabled.  Unlike the 'maxcallnumbers' option, this limit is not
; separate for each individual IP address.  Any connection resulting in a
; non-call token validated call number being allocated contributes to this
; limit.  For use cases, see the call token user guide.  This option's 
; default value of 8192 should be sufficient in most cases.
;
;maxcallnumbers_nonvalidated=1024
;
; The [callnumberlimits] section allows custom call number limits to be set
; for specific IP addresses and IP address ranges.  These limits take precedence
; over the global 'maxcallnumbers' option, but may still be overridden by a
; peer defined 'maxcallnumbers' entry.  Note that these limits take effect
; for every individual address within the range, not the range as a whole. 
;
;[callnumberlimits]
;10.1.1.0/255.255.255.0 = 24
;10.1.2.0/255.255.255.0 = 32
;

; The shrinkcallerid function removes '(', ' ', ')', non-trailing '.', and '-' not
; in square brackets.  For example, the caller id value 555.5555 becomes 5555555
; when this option is enabled.  Disabling this option results in no modification
; of the caller id value, which is necessary when the caller id represents something
; that must be preserved.  This option can only be used in the [general] section.
; By default this option is on.
;
;shrinkcallerid=yes     ; on by default

; Guest sections for unauthenticated connection attempts.  Just specify an
; empty secret, or provide no secret section.
;
[guest]
type=user
context=default
callerid="Guest IAX User"

;
; Trust Caller*ID Coming from iaxtel.com
;
[iaxtel]
type=user
context=default
auth=rsa
inkeys=iaxtel

;
; Trust Caller*ID Coming from iax.fwdnet.net
;
[iaxfwd]
type=user
context=default
auth=rsa
inkeys=freeworlddialup

;
; Trust callerid delivered over DUNDi/e164
;
;
;[dundi]
;type=user
;dbsecret=dundi/secret
;context=dundi-e164-local

;
; Further user sections may be added, specifying a context and a secret used
; for connections with that given authentication name.  Limited IP based
; access control is allowed by use of "permit" and "deny" keywords.  Multiple
; rules are permitted.  Multiple permitted contexts may be specified, in
; which case the first will be the default.  You can also override caller*ID
; so that when you receive a call you set the Caller*ID to be what you want
; instead of trusting what the remote user provides
;
; There are three authentication methods that are supported:  md5, plaintext,
; and rsa.  The least secure is "plaintext", which sends passwords cleartext
; across the net.  "md5" uses a challenge/response md5 sum arrangement, but
; still requires both ends have plain text access to the secret.  "rsa" allows
; unidirectional secret knowledge through public/private keys.  If "rsa"
; authentication is used, "inkeys" is a list of acceptable public keys on the 
; local system that can be used to authenticate the remote peer, separated by
; the ":" character.  "outkey" is a single, private key to use to authenticate
; to the other side.  Public keys are named /var/lib/asterisk/keys/<name>.pub
; while private keys are named /var/lib/asterisk/keys/<name>.key.  Private
; keys should always be 3DES encrypted.
;
;
; NOTE: All hostnames and IP addresses in this file are for example purposes
;       only; you should not expect any of them to actually be available for
;       your use.
;
;
;[markster]
;type=user
;context=default
;context=local
;auth=md5,plaintext,rsa
;secret=markpasswd
;setvar=foo=bar
;dbsecret=mysecrets/place	; Secrets can be stored in astdb, too
;transfer=no		; Disable IAX native transfer
;transfer=mediaonly	; When doing IAX native transfers, transfer 
			; only media stream
;jitterbuffer=yes	; Override global setting an enable jitter buffer
;			; for this user
;maxauthreq=10          ; Set maximum number of outstanding AUTHREQs waiting for replies. Any further authentication attempts will be blocked
;                       ; if this limit is reached until they expire or a reply is received.
;callerid="Mark Spencer" <(256) 428-6275>
;deny=0.0.0.0/0.0.0.0
;accountcode=markster0101
;permit=209.16.236.73/255.255.255.0
;language=en		; Use english as default language
;
; Peers may also be specified, with a secret and
; a remote hostname.
;
[demo]
type=peer
username=asterisk
secret=supersecret
host=216.207.245.47
;sendani=no
;host=asterisk.linux-support.net
;port=5036
;mask=255.255.255.255
;qualify=yes			; Make sure this peer is alive
;qualifysmoothing = yes		; use an average of the last two PONG
				; results to reduce falsely detected LAGGED hosts
				; Default: Off
;qualifyfreqok = 60000		; how frequently to ping the peer when
				; everything seems to be ok, in milliseconds
;qualifyfreqnotok = 10000	; how frequently to ping the peer when it's
				; either LAGGED or UNAVAILABLE, in milliseconds
;jitterbuffer=no		; Turn off jitter buffer for this peer

;
; Peers can remotely register as well, so that they can be mobile.  Default
; IP's can also optionally be given but are not required.  Caller*ID can be
; suggested to the other side as well if it is for example a phone instead of
; another PBX.
;

;[dynamichost]
;host=dynamic
;secret=mysecret
;mailbox=1234		; Notify about mailbox 1234
;inkeys=key1:key2
;peercontext=local	; Default context to request for calls to peer
;defaultip=216.207.245.34
;callerid="Some Host" <(256) 428-6011>
;

;
;[biggateway]
;type=peer
;host=192.168.0.1
;context=*
;secret=myscret
;trunk=yes			; Use IAX2 trunking with this host
;timezone=America/New_York	; Set a timezone for the date/time IE
;

;
; Friends are a short cut for creating a user and
; a peer with the same values.
;
;[marko]
;type=friend
;host=dynamic
;regexten=1234
;secret=moofoo   ; Multiple secrets may be specified. For a "user", all
;secret=foomoo   ; specified entries will be accepted as valid. For a "peer",
;secret=shazbot  ; only the last specified secret will be used.
;context=default
;permit=0.0.0.0/0.0.0.0


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