Tag: Asterisk

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Knowledge Base

Sip debugging with wireshark

Wireshark and Cloudshark are invaluable tools for debugging sip and iax issues on your Asterisk server.

Here we have a short Video that goes over the basics of getting a call captured and opened in Cloudshark

we also have a short tutorial for download here in PDF format

First we need to get the packets we want. This is far simpler than its thought. We use a simple command line tool called tcpdump, if its not installed install it now, You wont be able to live without it.

Here we have 2 commands, The first captures packets on interface eth0, -n means we won’t convert addresses, -w means we just capture raw packets and udp means its only the udp packets we want and finally port 5060 means its only the sip messaging we want. In the second we dont specify port 5060 so that we get the rtp stream as well.

/usr/sbin/tcpdump -n -i eth0 -w /tmp/wireshark.pcap -s2000 udp port 5060
 /usr/sbin/tcpdump -n -i eth0 -w /tmp/wireshark.pcap -s2000 udp
screen -S "udpDump" -dm tcpdump -n -i eth0 -C 9 -W 15 -w /var/log/asterisk/dumpsip.pcap -s2000 udp port 5060

The command above will write to file in the background and will rotate at 9 meg so suitable for cloudshark

Once you have started the capture and made a call as required you will get a file called for example /tmp/wireshark.pcap copy this to your workstation via ftp or sftp as you would copy any file.

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Products and services Services Support

Categories
Knowledge Base

Better SIP security

In Seven Steps

Original Text by J Todd March 28th, 2009

In case any of you were wondering why there has been a fairly notable upswing in the attacks happening on SIP endpoints, the answer is “script kiddies.”  In the last few months, a number of new tools have made it easy for knuckle-draggers to attack and defraud SIP endpoints, Asterisk-based systems included.  There are easily-available tools that scan networks looking for SIP hosts, and then scan hosts looking for valid extensions, and then scan valid extensions looking for passwords.You can take steps, NOW, to eliminate many of these problems.  I think the community is interested in coming up with an integrated Asterisk-based solution that is much wider in scope for dynamic protection (community-shared blacklists is the current thinking) but that doesn’t mean you should wait for some new tool to defend your systems.  You can IMMEDIATELY take fairly common-sense measures to protect your Asterisk server from the bulk of the scans and attacks that are on the increase. The methods and tools for protection already exists – just apply them, and you’ll be able to sleep more soundly at night.

Seven Easy Steps to Better SIP Security on Asterisk:

 

1) Don’t accept SIP authentication requests from all IP addresses.  Use the “permit=” and “deny=” lines in sip.conf to only allow a reasonable subset of IP addresess to reach each listed extension/user in your sip.conf file.  Even if you accept inbound calls from “anywhere” (via [default]) don’t let those users reach authenticated elements!

 

2) Set “alwaysauthreject=yes” in your sip.conf file.  This option has been around for a while (since 1.2?) but the default is “no”, which allows extension information leakage.  Setting this to “yes” will reject bad authentication requests on valid usernames with the same rejection information as with invalid usernames, denying remote attackers the ability to detect existing extensions with brute-force guessing attacks.

 

3) Use STRONG passwords for SIP entities.  This is probably the most important step you can take.  Don’t just concatenate two words together and suffix it with “1? – if you’ve seen how sophisticated the tools are that guess passwords, you’d understand that trivial obfuscation like that is a minor hinderance to a modern CPU.  Use symbols, numbers, and a mix of upper and lowercase letters at least 12 digits long.

 

4) Block your AMI manager ports.  Use “permit=” and “deny=” lines in manager.conf to reduce inbound connections to known hosts only.  Use strong passwords here, again at least 12 characters with a complex mix of symbols, numbers, and letters.

 

5) Allow only one or two calls at a time per SIP entity, where possible.  At the worst, limiting your exposure to toll fraud is a wise thing to do.  This also limits your exposure when legitimate password holders on your system lose control of their passphrase – writing it on the bottom of the SIP phone, for instance, which I’ve seen.

 

6) Make your SIP usernames different than your extensions.  While it is convenient to have extension “1234? map to SIP entry “1234? which is also SIP user “1234?, this is an easy target for attackers to guess SIP authentication names.  Use the MAC address of the device, or some sort of combination of a common phrase + extension MD5 hash (example: from a shell prompt, try “md5 -s ThePassword5000?)

 

7) Ensure your [default] context is secure.  Don’t allow unauthenticated callers to reach any contexts that allow toll calls.  Permit only a limited number of active calls through your default context (use the “GROUP” function as a counter.)  Prohibit unauthenticated calls entirely (if you don’t want them) by setting “allowguest=no” in the [general] part of sip.conf.

 

These 7 basics will protect most people, but there are certainly other steps you can take that are more complex and reactive.  Here is a fail2ban recipe which might allow you to ban endpoints based on volume of requests.  There is discussion on the asterisk-user and asterisk-dev mailing lists of incorporating this type of functionality into Asterisk – let’s hear your ideas!

 

If you’d like to see an example of the tools that you’re up against, see this demo video of an automated attack tool that does scan, guess, and crack methods via a click-and-drool interface.
In summary: basic security measures will protect you against the vast majority of SIP-based brute-force attacks.  Most of the SIP attackers are fools with tools – they are opportunists who see an easy way to defraud people who have not considered the costs of insecure methods.  Asterisk has some methods to prevent the most obvious attacks from succeeding at the network level, but the most effective method of protection are the administrative issues of password robustness and username obscurity.

 

JTodd
Digium
Categories
Asterisk Support Elastix Support Knowledge Base OpenVox

Asterisk pickup groups

The aim here is to explain the relationship between the callgroup and pickup group settings in extension conf files of an Asterisk server and named pickup in freepbx, we will use numbers but not names (see explanation below).

Call Pickup is the abilty to pickup a ringing phone from another phone.

The ability to do this is defined in the extensions conf file.

In many systems there is only on setting to do this normally “pickup group” you add extensions to this group and they can pickup calls ringing at members of the group. Obvious really.

Now Asterisk goes one better. You can define the callgroup and pickup group, This way you define who you can pickup and who can pickup you. This is very useful for operators, who for example don’t want calls picked up of them but do want to pickup calls from all other users.

So how do you define it.

In our example we will have 4 phones defined as follows

Callgroup Pickupgroup
201 2 1-2
202 1-4 1-4
203 2,4 2,4
204 1 1

And who can do what when trying t pickup is as follows

Ringing Phones attempting Pickup
Call to 201 204 PU failed 203 PU Passed
Call to 202 201 PU passed 203 PU Passed
Call to 203 201 PU passed 204 PU failed
Call to 204 201 PU passed 203 PU failed

So from this we can see that its the Pickupgroup that defines what callgroup can be picked up.

So because 201 has a callgroup of 2 Only sets who’s pickup group includes 2 can pick up the call. whereas as 201 has a pickupgroup of 1-2 it can pickup calls from callgroups 1-2.

For example you may have 6 pickup groups defined with users only allowed to pickup their own group members except an operato who wishes to be able to pick everyone up and a PA who has a college who she wants to be able to pickup

So all normal users would have their pickup and callgroup the same. The PA would have the pickupgroup defined with both the group numbers but only its own call group. And finally the operator would have a callgroup of 0 and its pickupgroup of 1-6.

Named call pickup groups

Named pickup groups are new with Asterisk 11. And are now supported in FreePBX , But be careful even though the ‘hint’ says they can be numeric or names the just use the named variable.

namedcallgroup=office,home,1
namedpickupgroup=office,home

As above we have a namedcallgroup as 1 but this is not the same as callgroup 1

A named callgroup and pickupgroup can be set to a comma separated list of case sensitive name strings. The number of named groups is unlimited. The number of named groups you can specify at once is limited by the line length supported.

SYNTAX
namedcallgroup=[name[,name[,...]]]
namedpickupgroup=[name[,name[,...]]]
  • namedcallgroup – specifies which named pickup groups that this channel is a member.
  • namedpickupgroup – specifies which named pickup groups this channel can pickup.
Configuration Example
namedcallgroup=engineering,sales,netgroup,protgroup
namedpickupgroup=sales

Configuration should be supported in several channel drivers, including:

  • chan_dahdi.conf
  • misdn.conf
  • sip.conf
  • pjsip.conf

pjsip.conf uses snake case:

named_call_group=engineering,sales,netgroup,protgroup
named_pickup_group=sales

You can use named pickup groups in parallel with numeric pickup groups. For example, the named pickup group ‘4’ is not the same as the numeric pickup group ‘4’.

Numeric call pickup groups

(obsolete use named groups)

A numeric callgroup and pickupgroup can be set to a comma separated list of ranges (e.g., 1-4) or numbers that can have a value of 0 to 63. There can be a maximum of 64 numeric groups. This is important to note as Freepbx does not sanity check what you put in there, So you can put 70 in the Gui and it will show 70 but do a sip show peer or a pjsip show endpoint and you will see its not set.

Categories
Knowledge Base Technical

Nagios plugin for reading the Asterisk Database

This is a simple plugin that is based on one by Jason Rivers We have changed it now to read the ASTDB (Asterisk internal Database and then based on ok and Critical keys it will report OK or Critical staus reports to Nagios.

This was written for reporting if an Elastix system is in Day or Night mode.

You can define the Database Family, Key, Critical value and OK value. This means you can cutomise it to what ever you need to report.

 

The Code is below, make you may need to change /usr/bin/nc for what ever you use for netcat.

any issues email us, but dont forget this is given for free not supported for free.

#!/bin/bash
#
# Program : check_asterisk_ami
# :
# Author : Original code by Jason Rivers < jason@jasonrivers.co.uk >
# : Modified by Cyber-cottage.co.uk for checking the asterisk Database
# :
# Purpose : Nagios plugin to return Information from an Asterisk host using AMI
# :
# Parameters : --help
# : --version
# :
# Returns : Standard Nagios status_* codes as defined in utils.sh
# :
# Licence : GPL
#
# Notes : See --help for details
#============:==============================================================
PROGNAME=`basename $0`
PROGPATH=`echo $0 | /bin/sed -e 's,[\/][^\/][^\/]*$,,'`
REVISION=`echo '$Revision: 1.1.0.6 $' | sed -e 's/[^0-9.]//g'`
. $PROGPATH/utils.sh
print_usage() {
echo "Usage: $PROGNAME [-H hostname] [-u username] [-p password] [-P port] [-k DBkey] [-c critical] [-o ok] [-f family]"
echo " -H Hostname"
echo " -u AMI Username"
echo " -p AMI Password"
echo " -P (optional) AMI PORT"
echo " -k Database key"
echo " -f Database family"
echo " -c Critical Key"
echo " -o OK KEY"
echo ""
echo "SupportedCommands:"
echo " Most DB familiys that toggle such as DayNight in elastix"
echo "Usage: $PROGNAME --help"
echo "Usage: $PROGNAME --version"
}
print_help() {
print_revision $PROGNAME $REVISION
echo ""
echo "Nagios Plugin to check Asterisk ASTDB using AMI"
echo ""
print_usage
echo ""
echo "Asterisk Call Status Check. orignal version by © Jason Rivers 2011 changes to do ASTDB by cyber-cottage.co.uk"
echo ""
exit 0
# support
}
# If we have arguments, process them.
#
exitstatus=$STATE_WARNING #default
while test -n "$1"; do
case "$1" in
--help)
print_help
exit $STATE_OK
;;
-h)
print_help
exit $STATE_OK
;;
--version)
print_revision $PROGNAME $REVISION
exit $STATE_OK
;;
-V)
print_revision $PROGNAME $REVISION
exit $STATE_OK
;;
-H)
REMOTEHOST=$2;
shift;
;;
-P) AMIPORT=$2;
shift;
;;
-u) AMIUSER=$2;
shift;
;;
-p) AMIPASS=$2;
shift;
;;
-c)
CRITICALNAME=$2
shift;
;;
-o)
OKNAME=$2
shift;
;;
-k)
DBKEY=$2;
shift;
;;
-f)
FAMIL=$2;
shift;
;;
*)
echo "Unknown argument: $1"
print_usage
exit $STATE_UNKNOWN
;;
esac
shift
done
if [ "${AMIPORT}" = "" ]; then
AMIPORT="5038"
fi
if [ "${FAMIL}" = "" ]; then
##WARNING
echo="CRITICAL: Unknown KEY"
print_help
exit=$STATE_CRITICAL
else
## Checking Astdb
CHANNELS=`/bin/echo -e "Action: login Username: ${AMIUSER} Secret: ${AMIPASS} Events: off Action: DBGet Family: ${FAMIL} Key: ${DBKEY} Action: Logoff " | /usr/bin/nc $REMOTEHOST ${AMIPORT} | awk '/Val/ {print $2}'|tr -d " "`
if [ "$CHANNELS" = "" ]; then
echo "UNKNOWN: Unable to get ASTDB status"
exit $STATUS_UNKNOWN
fi
if [ "$CHANNELS" = "${OKNAME}" ]; then
exitstatus=$STATU_OK
MSG="OK: ${DBKEY} Asterisk Emergency message not active"
elif [ "$CHANNELS" = "" ]; then
exitstatus=$STATU_WARNING
MSG="WARNING: Asterisk Unknown status"
elif [ "$CHANNELS" = "$CRITICALNAME" ]; then
exitstatus=$STATU_CRITICAL
MSG="CRITICAL: ${DBKEY} Asterisk Emergency message active"
fi
fi
echo $MSG
exit $exitstatus
Categories
Knowledge Base Technical

Installing Webdav on Centos with untrusted ssl certificates

Webdav (Web-based Distributed Authoring and Versioning) is a set of methods based on the Hypertext Transfer Protocol (HTTP) that facilitates collaboration between users in editing and managing documents and files stored on World Wide Web servers.This can be useful to allow backing up of data between servers. In Linux there is a command line client called cadaver that in theory allows you to script its use.

This isnt as staight forward as it could have been and we spent half a day and a lot of Googling to get to the bottom of common problems, Such as auto loging in, Untrusted ssl certificates and scripting.

So here is a simple run down on what you have to do to script with webdav and cadaver

Install cadaver

yum install cadaver

once installed you will need to install the certificate for the untrusted ssl site

for example
wget http://website/untrusted.server.com.cer
now convert this to a .pem file
openssl x509 -inform der -in untrusted.server.com.cer -out untrusted.server.com.pem

now add this to your cert.pem file.

in centos this seems to be in the  /usr/share/ssl/ directory
cat untrusted.server.com.pem >> /usr/share/ssl/cert.pem

you now need to edit the ./netrc file with the server and logon details
vi ~/.netrc

machine untrusted.server.com
login   user
password        secret

save the file.

now when you connect you wont be promted for accepting the certificate or a username and password

cadaver -et  https://untrusted.server.com
dav:/>

Ok now we want to script the actions.
This is as simple as creating a script file.

for example

vi ~/.cadavscript
ls
pwd
quit

will give the following output

cadaver -et  https://untrusted.server.com/ < ~/.cadavscript
dav:/> Listing collection `/’: succeeded.
test.txt                              35  Aug 19 15:04
dav:/> Current collection is `https://untrusted.server.com/’.
dav:/> Connection to `untrusted.server.com’ closed.

So create a script to do what you want and your done

Categories
Design Installation Services Support Technical

Gradwell Approved Professional

A Gradwell Approved Professional (GAP) has a core set of knowledge required to succeed with the Gradwell product set and systems. To become a Gradwell Approved Professional partners must pass an examination and show an in depth knowledge of Gradwell Products and Voip Support.

This means you can be confident that they can:

  • Achieve consistent roll outs of reliable business telephony services.
  • Confidently resolve end user technical issues within an acceptable time frame.

To signup to Gradwell services with us CLICK HERE

Categories
Peripherals Products

The Algo 8180 SIP Audio Alerter

The 8180 SIP Audio Alerter is a loud ringing, paging and intercom device for use with SIP telephone systems. It has two main uses. The first is as a loud ringer for use in places such as warehouses. The second use is as a paging and intercom system. It can operate in both these modes at the same time by appearing as two different extensions on your phone system at the same time.

When registered with a SIP server, one endpoint will play an audio file from internal memory upon ring detection. The second endpoint will auto-answer for voice paging or full intercom (two way audio).

Equipped with a high efficiency integrated amplifier and tuned high quality loudspeaker, the 8180 is typically eight times louder than a telephone speaker. Several audio files are pre-loaded into the 8180 internal memory for ring sounds but users may also record or upload custom audio files, music, sound effects, or voice announcements.

Ambient noise monitoring

The advanced features of the 8180 include SoundSureTM technology which automatically adjusts loud ring and loudspeaker volume to compensate for background ambient noise. Ideal for variable noise environments (restaurants, workshops, classrooms, etc.), SoundSureTM ensures that ringing or paging is always heard but not unnecessarily loud.

Applications / Usage scenario

  • Loud Ringer in noisy or variable noise environments (classroom, restaurant, machine shop)
  • Voice Paging (warehouse, workshop)
  • Outdoor ringing or paging
  • Multi-cast wide area notification

Easy to Install

  • Network managed SIP endpoint
  • Configuration is possible using the feature buttons or web interface
  • PoE eliminates local power supply

Features

  • Voice Paging with talkback capability
  • High efficiency and high output wideband speaker
  • Multicast receive or broadcast capability
  • Outputs for external speaker, slave amplifier, or visual alerter
  • Dual purpose loud ringing and/or talkback voice paging
  • Significantly louder (eight to twenty times) than typical telephones
  • Low frequency tones outperform traditional shrill electronic ringers
  • SoundSureTM ambient noise compensation adjusts output for noise level
  • Multicasting capability for wide area notification

Customisable

  • Pre-loaded with several ring tones including bell, chime, gong, buzzer, warble, and dogs
  • Supports custom uploaded WAV files or recorded messages
  • Selectable/customisable alert tones or announcements

Please contact for pricing and avalibility

Categories
Case Studies Technical

Man In The Middle

Man In The Middle Server, What does he mean I hear you ask?

Well its the best term for it, as it describes what it is and does. Basicly we have an AsteriskServer sitting in between the incoming lines and the main  PBX. Idealy We would have liked to replace the existing PBX but in some cases this just isnt possible and we have to accept this.

So why may we need to do this, Well we have used this solution to allow customers to have follow the sun  support call centers.  Calls arrive to a dedicated DDI number that is for support in that country and depending on the time of day it is routed to the call center that is open in another part of the world over a voip network. This is done by Asterisk checking the called number of all calls and if a match is made the call is passed off to Asterisk to handle the call in its dialplan, all other unmatched calls are passed on to the main system.

We have also used this method of connection to play prompts to callers before the call is sent to the main system. Calls in this case can be identified by CallerID name or number. So for example calls from the BT operator, International payphones or even just a certain CallerID Number are played a specific message and then either forwarded on or passed on to a IVR (Interactive Voice Response menu) to be handled in a specific manner.

A another often used reason for this type of connection is when migrating from a legacy pbx to and Asterisk server. The line connections are the same and the call flow is controlled by the dialplan, Routing calls on teh Asterisk system to its dialplan and routing calls for extensions still on the old system to it.

Once all extensions are migrated to the new system the old system can be turned off and removed with no interuption to the users on the new system.

Categories
Knowledge Base

General Configuration Guide Skype for SIP and Asterisk

 

If you are new to SIP, Asterisk is a useful, open-source (GPL) platform with which to test and experiment with the Skype for SIP. This is a guide on how to install Skype for SIP on a system agnostic or “vanilla” Asterisk server.

 

To install Asterisk on your server, please see the Digium documentation here http://www.asterisk.org.

 

This configuration guide is based on Debian Linux (Lenny 64bit). With a basic installation of Debian you can install Asterisk by issuing the following APT command at the command line:-

apt-get install asterisk

 

 

Configuration Files for Vanilla Asterisk

 

In configuring Skype for SIP on a vanilla Asterisk system we are primarily concerned with two configuration files:-

 

  1. sip.conf (located in the /etc/asterisk/ directory)
    The sip.conf file holds the registration details for the Skype for SIP channel
  2. extensions.conf (located in the /etc/asterisk/ directory)The extensions.conf holds the dial plan telling Asterisk what to do with incoming and outgoing calls.-

 

Let’s do a walkthrough of the configuration steps.

 

Configuring the sip.conf File

 

Step 1

 

The sip.conf file has two sections that need to be completed. The “General” section (denoted in the file with the [general] heading) and peer section denoted in the file with the [peers] heading.

 

In the General section we need to add a “register” line. This tells Asterisk to register with Skype at the Skype local point of presence.

 

Add the following, under the “[general]” section in the file, substituting your 9905xxxx number and password with your actual credentials for the Skype for SIP profile you wish to use. Your SIP Profile details can be found in the Skype Business Control Panel (BCP):-

 

register => 99051000xxxxxx: PaSsW0rD@sip.skype.com /99051000xxxxxx

 

Step 2

To ensure that we also receive the callerID from Skype clients we also should add:-

 

trustrpid = no

sendrpid = yes

 

 

Step 3

Next, we add a section for the peer, in the “[peers]” section of the sip.conf file. Again we substitute the 9905xxxxx number and password with the SIP Profile credentials from the Skype Business Control Panel (BCP):-

 

[99051000xxxxxx]

type = peer

username = 99051000xxxxxx

fromdomain = sip.skype.com

fromuser = 99051000xxxxxx

realm = sip.skype.com

host = sip.skype.com

dtmfmode = rfc2833

secret = PaSsW0rD

nat = no ;This should be set to reflect your network NAT configuration

canreinvite = no

insecure = invite

qualify = yes

disallow = all

allow = alaw

allow = ulaw

;allow = g729 ; Uncomment this if you have G729 licences

amaflags = default

trustrpid = no

sendrpid = yes

context = skype_in

 

Please Note:

If your Asterisk PBX is behind a NAT device, you should set “nat = yes” in this section.

 

If your Asterisk PBX has a dedicated internet IP address, set this to “nat = no”.

 

Step 4

After setting these changes, reload the Asterisk’s SIP module by typing:-

 

asterisk -rx “reload chan_sip.so”

 

…….at the command line.

 

Step 5

After the SIP Module has reloaded enter asterisk -rx “sip show peers” at the command line, which should return:

 

pbx*CLI> sip show peers

Name/username Host Dyn Nat ACL Port Status

99051000xxxxxx/99051000xx 193.120.218.68 5060 OK (52 ms)

 

Then enter asterisk -rx “sip show registry” which should return:

 

pbx*CLI> sip show registry

Host Username Refresh State Reg.Time

sip.skype.com:5060 99051000xxxx 105 Registered day, dd mmm yyyy hh:mm:ss

 

If you see output similar to the above, then you are registered to the Skype SIP gateway and ready to make and receive calls.

 

We now need to setup the extensions.conf so that we have a dialplan setup and Asterisk knows how to deal with incoming and outgoing calls.

 

Configuring the extensions.conf File

 

The extensions.conf file requires a “context” and an “extension” to be added for incoming Skype calls, plus an extension to be added to the context that users use for outgoing calls.

 

Incoming “context”

 

Add the following lines to the [context] section of extensions.conf, substituting 9905xxxxxxx with the 9905 number for the SIP Profile. Again you can find the details of your Skype SIP Profiles in the Skype BCP:-

 

[skype_in]

exten => 99051xxxxxxxx,Noop(${CALLERID(name)} , ${CALLERID(num)})

exten => 99051xxxxxxxx,n,Dial(SIP/100,30,t,r)

exten => 99051xxxxxxxx,n,voicemail(100|u)

 

This is a simple “vanilla” context that shows us the callerID name and number, dials extension 100 for 30 seconds and finally, if unanswered, goes to voicemail. This sequence will need to be amended to suit your requirements. If you are planning on having many SIP Profiles or Online Numbers that all need to end up at the same destination, or the destination is decided by the Skype Business Account that the online number is registered against, a more complicated Dialplan can be used. For example:-

 

[skype_in]

exten => 99051xxxxxxxx,1,Noop(${CALLERID(name)} , ${CALLERID(num)})

exten => 99051xxxxxxxx,n,Queue(sfs|r|||40)

exten => 99051xxxxxxxx,n,voicemail(100|u)

 

 

Outgoing “Context”

 

The outgoing context must be included in the context for your user’s phones. Usual security measures apply. Do not include this in a context for incoming calls.

 

[skype_out]

 

exten => _90Z.,1,Set(CALLERID(num)= 99051xxxxxxxx)

exten => _90Z.,n,Dial(SIP/0044${EXTEN:2}@99051xxxxxxxx)

 

exten => _900.,1,Set(CALLERID(num)= 99051xxxxxxxx)

exten => _900.,n,Dial(SIP/${EXTEN:1}@99051xxxxxxxx)

 

 

In the sip.conf add the following to create user 100

 

[100]

secret=secret

mailbox=100

callerid=”myskypetrunk” <100>

type=friend

host=dynamic

context=international

;nat=no

nat=yes

canreinvite=no

dtmfmode=rfc2833

pickupgroup=1

callgroup=1

subscribecontext=default

notifyringing=yes

disallow=all

;allow=alaw

allow=ulaw

allow=gsm

 

in the extensiosn.conf add the following to the default context

 

exten => _XXX,1,Dial(SIP/${EXTEN},20)

 

Also create a context called international

 

[international]

include => default

include => skype_out