Asterisk Encryption August 10, 2007
Posted by bbarrett in Asterisk, VoIP.add a comment
Recently we were investigating the privacy controls one can put in place with Asterisk. I found that Asterisk does not yet have support for SRTP or SIP over TCP (which would enable secure SIP using TLS).
VoIP calls – like all network traffic – can be listened to by potentially malicious people. However voice calls are probably in greater need than other network traffic because it tends to be more personal. People have grown to trust phones as the best alternative to face to face correspondence for privacy. People would not be happy knowing that a third party could record their conversation and play it back at a later time. However, not all voice traffic needs encrypting – after all the chances of a malicious user on an internal network is very low.
Asterisk Realtime IAX2 Trunks July 31, 2007
Posted by epower in Asterisk, Asterisk.realtime, VoIP, realtime.add a comment
As Brian mentioned, Realtime is a favorite subject of ours. And so I needed to set up a number of IAX2 trunks using Realtime (long story).
Using multiple servers and one database with regserver July 24, 2007
Posted by bbarrett in Asterisk, VoIP, realtime.3 comments
Asterisk’s Realtime is a favourite subject of ours apparently. We have a phone system here in the TSSG, which consists of one Asterisk machine inside our network and another external to the network peered with it. They both share the same database so a user can register on either machine.
Cheating around ‘include’ in Asterisk realtime July 17, 2007
Posted by bbarrett in Asterisk, func_odbc.3 comments
Asterisk’s realtime configuration has many benefits, no more dropped calls when changing minor things or adding users. You can put your entire dial plan into realtime… almost.
One of the biggest differences between extensions.conf and Asterisk’s Realtime dial plan is that one can no longer include other contexts into another context. This is the classic way of building an tiered dialling rule hierarchy, create the most restrictive context, then use ‘include’ to add more and more allowed numbers. (more…)
Some more IPv6 SIP clients… May 31, 2007
Posted by bbarrett in Asterisk, ipv6.add a comment
In addition to “Spider phone”, I have found a few more IPv6 enabled soft phones.
Linphone on Linux works, at least when you have a Quad A DNS record for your registrar. However, I could not seem to use a raw IPv6 address as a registrar address. The other Linux offering was “Kphone”, but I found that it’s IPv6 support was a minor branch last updated in 2004, so when I finally got it compiled it segfaulted instantly.
A Java client I found, “SIP-communicator”, works OK on Windows. Using the default Debian package provided it installs under Linux but doesn’t seem to run.
Finally “AGEphone”. It isn’t great, as it’s free version only support calls or up to 1 minute, but it suffices for testing.
Basic func_odbc starting point May 30, 2007
Posted by epower in func_odbc.5 comments
As I’ve already mentioned, I needed to solve some problems in Asterisk and the best method I’ve found was using func_odbc. Getting started with it wasn’t too tricky but it does have it’s quirks and that’s what I’ll be talking about today.
Asterisk IPv6 experimental branch tests May 25, 2007
Posted by bbarrett in Asterisk, ipv6.add a comment
As alluded to by Niall I have been testing Marc Blanchet’s port of Asterisk to IPv6. Apart from a minor error ( minor code wise, but it had the implication of rejecting all incoming SIP registrations! ), it works quite well. It peers with an IPv4 Asterisk server just fine.
Much more difficult was the location of a suitable client to test it with. Read Niall’s entry to find out more about Counterpath’s “offering”, but I found an Asian client that worked quite well, “Spiderphone“. I tried a windows port of “Linphone”, but it failed to register properly. It must be noted that the windows port is behind the Linux version, so it possibly works much better there. Other Linux based phones such as “Kphone” also claimed IPv6 support but I could find any windows version of them.
A significant portion of Asterisk’s code SIP base is dedicated to overcoming the problems of SIP with NAT, I would estimate. This kind of problem would disappear with IPv6. But right now there is kind of a chicken and egg situation regarding VoIPv6, there is little in the way of an IPv6 SIP infrastructure and few clients. Hopefully when IPv6 support gets enabled in Asterisk’s trunk code base half that problem will no longer apply and more client programs will be moved to IPv6.
Asteriskv6 – EyeBeam May 25, 2007
Posted by ieniall in Asterisk.add a comment
counterpath3.jpg
Recently we tried to get Asteriskv6 (developed by Mark Blanchet at http://www.viagenie.ca/ ) working on our testbed in work. After a bug found in chanSIP and corrected ( thanks to Brian ) we sucessfully registered an IPv6 client to the running server. However, the amount of IPv6 useragents available and moreover the quality of these agents is quite bad.
We decide to purchase some eyebeam clients ( the paid version of X-Lite) to test out on the system. On the Counterpath website they clearly state that EyeBeam has IPv6/AAAA support – See attached Image. However, this is not the case. They require you to purchase large amount of licences to get IPv6 support for eyebeam claiming that your only purchasing their “retail” version. Clearly their website dosent state this case. The search is back on for an IPv6 user agent that works!!
A perfect world — > End to End Voip calls………
Asterisk Realtime – Flat files to DBMS May 24, 2007
Posted by ieniall in Asterisk.2 comments
Asterisk Realtime is a set of drivers and tools that enable, developers mainly, to move the static Asterisk configuration files (normally kept in /etc/asterisk) into databases such as MySQL. It comes in too flavours “Static and Dymanic Realtime”.
Firstly, putting Static and the word “RealTime” in the same sentence is probably technically incorrect, however the two methods of enabled RealTime are quite different. With dymanic realtime, users and extensions can be added on the fly without reloading Asterisk. Within the T.S.S.G. we are looking into methods of allowing multiple people access the same PBX while delivering common services. Dynamic realtime seems to do exactly what we want. Static on the other hand requires a reload when a change is made, if its an urgent change calls will be dropped on the PBX.
Realtime has one major flaw in my opinion, its incapacity to handle the ” include => context ” dialplan logic code. However, we are currently looking into a work around using mySQL and func_ODBC. More on that later …..
Digium have posted a “patch” on the matter, however we are going to use the Vanilla Version of Asterisk ( 1.4.2 )
Working with func_odbc May 24, 2007
Posted by epower in func_odbc.add a comment
There comes a time with Asterisk, when you encounter a problem which can’t be solved with clever dial plan logic but you don’t want to wheel out AGI just yet. Over the next while, I’ll be posting some work I’ll be doing with ‘func_odbc’, a handy little feature of Asterisk that lets you query databases using SQL templates and ODBC.
