One of the first pieces that I dabbled with was setting up paging and conference calls. When I was testing conference calling, the conference would disconnect almost immediately. From my past experience with Asterisk, I know that Asterisk needs a timinig source. Most larger/enterprise PBX units would not have a trouble as they would be using an analog or digital interface card which provides the timing required. In my case, I am working with nothing but VoIP, so I have no interface card to provide a timinig source. In the past, a dummy driver is provided that can be loaded to allow Asterisk to interface with the Linux kernel’s timinig capabilities.

The only problem is that I can’t locate the module either in the directory where it should have been located or through an automated search of the filesystem. I was truly stuck. Of course, I turn to Google. Surprisingly, Google turned up no answers to where this driver could be locataed without recompiling the drivers. I am not normally hesitant to compile code, as the developers make this easy. My instincts told me there had to be a provision for handling this problem with the distribution as-is.

Fortunately, I had one more source of answers that I had in my back pocket. I fired up my IRC client and connected to the #asterisk chat room on the Freenode IRC network. The regulars there include folks who live and breath Asterisk every day, so I know the folks there have the answers I need. Naturally, after I posed my question to the room, a quick answer was offered. I needed to open /etc/dahdi/modules and comment out all references to hardware drivers, followed by a restart of the dahdi service. When I restarted the dahdi service, it reported that dahdi_dummy was loaded. Apparently, the dahdi driver assumes that if no other drivers are to load, then use the default driver to provide dahdi_dummy to allows conferences to work.

Second, I wanted to keep an eye on what calls I was making and receiving. FreePBX includes the capability on a “Reports” tab on the interface. I have also had previous experience fixing this issue. While the tool works, no data is saved to the database to search. For whatever reason, the asterisk16-addons-mysql package is not installed by default. Installing the package and restarting Asterisk allows the reporting to work as expected.

Finally, an issue occured during the initial configuration of this Asterisk system which would have prevented the saving of a new configuration. After making changes within the FreePBX interface, the administrator needs to apply the changes. When I first attempted to apply the changes I made to the system, I received an error message regarding the “retrieve_conf” script not running. Google was able to turn up the answer. By default, both the iptables firewall and the SELinux addon are activated by default. I used the built-in setup utility to turn off each of those services; the script worked immediately.

After a crazy two days of work, investigation, and both frustration and fun, my Asterisk phone system is finally where I want it. I have inbound and outbound calling on two phone numbers on a single trunk and connected to two internal SIP devices. CallerID is being sent for the correct number and I have a basic conference room setup. There are lots of tweaks and additions that I would like to make, but I think I will leave that to another entry after I have made them.

My first task was to create internal extensions and configure the phones to use those extensions. Very little trouble was had in getting my Linksys PAP2T-NA analog phone adapter to function. My Cisco 7940 is always a little trickier, just because of the provisioning capabilities. I had to adjust the FreePBX configuration to turn off NAT for that device, as my 7940 always stays here in my network. Otherwise, the configuration consisted of setting proxy information and matching secrets on the phones.

Next, I set about configuring outbound telephony service. I prefer a provider who can give service via the IAX protocol, as it was created by the Asterisk developers to compensate for some of the drawbacks of the SIP protocol. My provider, who I can’t recommend enough, is TelIAX. I configured the trunk information and it registered and came up immediately. With FreePBX, inbound and outbound routes are configured independently of trunk connectivity and each other. I set up an inbound route for my primary phone number and an outbound 10-digit dialling route.

Each of my two phones were able to make and receive calls both internally and externally. At this point, my phone system is considered usable. Finally, I can relax and take some time to enjoy the fruits of my labor. However, not everything is entirely up to my standards, a few loose ends need resolved. Stay tuned for more…

The most obvious route was to install the CD as-is. Unfortunately, this machine has no optical drive attached, and I did not feel like opening the system and adjusting the cabling to support that. I also don’t have a USB/IDE adapter. So, I first thought to use Unetbootin to install from a USB flash drive. After using Unetbootin to place the files on the flash drive, I attempted to boot to it. The motherboard supports USB floppy drives and CD-ROM, but not flash drives.

My next trick was to attempt to boot the ISO over the network, which I have successfully done with pfSense and the Debian install CD. A quick copy of the ISO into my TFTP boot directory and a modification to the PXE boot config were all that were necessary before rebooting my phone system. The PXE boot system comes up, and I attempt to boot the ISO. I was hopeful, but this worked like the rest of this install, an epic fail. Looking at the logs, I discovered that the TFTP server can’t handle serving a 650MB ISO, while it has easily handled a 60 and a 130 MB one. Another dead end, or is it?

I stepped back to think about the situation… If I can’t boot the ISO, what can I do? I remembered that when I copied the ISO to the TFTP root directory, I also copied the extracted files that Unetbootin has placed on the flash drive. I knew that PXE and USB booting, as implemented on Linux, are very similar. I configured the PXE environment to boot the extracted kernel. I was delighted to see that the installer loaded at all, after everything that had not worked as expected so far.

Once the installer started, it could not find the packages to install and asked which method to use to locate the packages. One of the HTTP. I created a new symbolic link in Apache’s DocumentRoot pointing to the TFTP root directory, making it accessible via HTTP. The installer immediately found the files and was able to install almost all of the packages. One package couldn’t be found, due to Unetbootin truncating the name. I renamed the file and clicked retry in the installer. The installer finished successfully. I rebooted and was able to log into the system.

After all of this craziness, I was ecstatic at being able to finally have a usable web interface on my phone system. Now, it’s on to configuring the system… Enjoy part 3…

At the time, the dialplans and routing all needed to be crafted by hand, in the early 1.2 days. A healthy portion of my time was involved in learning about extensions, contexts, and priorities. As I looked forward to implementing Asterisk at home, I found a fun device called the Linksys NSLU2, affectionately nicknamed the “Slug.” After attaching a 4GB flash drive, I installed Debian and Asterisk, again with a handcrafted dialplan. Fast forward another year, I had upgraded the hardware to a Mini-ITX system with a hard drive and no CD drive, Through all this time, I was hand-crafting a dialplan.

While my knowledge of Asterisk dialplans grew, several web interfaces became usable. I and some close friends tried to use the AsteriskGUI created by Digium from the original AsteriskNOW distribution. At the time, the AsteriskGUI was somewhat usable but had some significant bugs; I continued to use Asterisk with a hand-written dialplan. Since then, Trixbox was the biggest proponent of the FreePBX. Once AsteriskNOW added FreePBX as an option, I figured it was worth a try. After setting up a demo system and dabbling with it, I was pleased. My only hestiation was that the base distribution was and is CentOS, which is a fine base, but I tend to prefer Debian-based distros…

With that in mind, I have tried at least 3 or 4 times over the last few years to install FreePBX on my existing Debian-based system with its custom dialplan. Each time, I have fallen short of getting it setup. Mostly, I just haven’t invested the time to really solving that problem. In stead, I had the chance to spend the evening helping my buddy Mike learn all about Asterisk. We spent the time with the newest 1.7 version of AsteriskNOW. It was fairly clear, after some experimentation, that I needed to leverage this much more flexible tool to maintain my phone system. I tried one final time to install FreePBX on my phone system, with the same results as before, incomplete with too many holes and issues for me to spend my time with.

That night, after Mike had gone, I resigned myself to replacing that Debian base with the CentOS base of the AsteriskNOW distribution, figuring this was easier. Of course, nothing about this install was easy. I’ll share more in part 2…

I began investigating by looking into the metadata for the voicemails which were left; all were from unusual phone numbers outside of our area code.  My next trip was to the CDR records and my provider’s call history.  These sources showed that over 1000 phone calls were attempted to be connected through our phone system to various communities around the country.  Two patterns emerged while looking at the details of the calls:

• The calls were being generated in a non-sequential pattern; clearly an unscrupulous telemarketer was war-dialing to South Carolina, Michigan, and Virginia.
• All of the outbound calls were originating with my girlfriend’s CallerID.

So, I knew what was going on, but I had yet to determine to how this incident occured.  Further digging revealed that the Linksys ATA being used internally was lagging significantly and intermittently.  It was a moment of epiphany; I understood where the problem was, and I could take action to address it.

Several years ago, I installed an Asterisk server to provide home phone service with a company that provided an IAX trunk.  At the time, all we were using softphones to make and receive calls.  Over time, I upgraded to a Cisco 7940 for myself and an analog cordless phone on a Linksys ATA for my girlfriend.  At the time I installed the ATA, I had not used a significant amount of security of the SIP peer registration, as the network was firewalled from the Internet.

Fast forward to 5 months ago…  I obtained a business phone service through a major provider using SIP.  Due to their configuration, I was required to open the SIP and RTP ports to the general Internet and forward them to my Asterisk server.

Now, we return to the present time.  Several days ago, this telemarketer scanned my router, found open SIP ports, and began to issue a brute-force attack against my Asterisk server.  The telemarketer scanned every possible 3 and 4 digit peer name, was able to find the Linksys ATA’s peer name, and was quickly able to brute-force the password.  With this information, the telemarketer was able to register as that peer and make calls outbound, according to the dialplan configured for my girlfriend.  My Cisco’s peer was not impersonated, but it would not be likely to be responsible for outbound calling due to the unique dialplan I am using.

With the understandng of what has happened, I could work to correct and block the means by which this telemarketer was using my phone system and service:

1. I unloaded chan_iax.so to remove the possibility of additional phone calls being made.
2. I then enabled a moderate amount of security, particularly a random password for each of my SIP devices.
3. Next, I modified my firewall configuration to drop all packets through my router which contained the IP address from which the attack came.
4. I then re-enabled the IAX phone service by reloading the chan_iax.so module.

After the initial security containment, I turned my focus to handling the inbound phone calls being returned based upon the messages left with the various victims around the country.  I recorded an announcement indicating what had happened and that the compromise was taken care of.  Finally, I crafted the dialplan to play this announcement to every caller not from a local phone number.

Overall, this breach was not as extensive as it could have been, but it does illustrate that security must be vigilantly monitored and maintained.  My complacency in the security of my network ultimately led to this incident.  Fortunately, it does not seem to have led to any major financial loss to any party, including myself.

For a soundtrack fan like myself, the concert had a great blend of music from the old classics like medleys of the music from the Mario and Zelda series to contemporary classics such as Halo and World of Warcraft.

This show was a bit unique, for me.  First of all, the amazing pianist Martin Leung performed live at the show.  Using the 3-story pipe organ in Mershon Auditorium, he played a suite of music from Castlevania.  For some recorded bits before he began touring with VGL, check out what is available on Google Video.  Notice that he is playing blindfolded to start with.

I would like to go back to the show.  It’s nearest touring to my area is in Fort Wayne in February.

Of course, this isn’t the only concert of its kind.  Other video game concerts have run the world over, but VGL is the biggest domestic concert series.  One of it’s brethren is Distant Worlds: Final Fantasy. While VGL spends time in all sorts of genres of music and games, Distant Worlds is focused specifically on the Final Fantasy series of games. The next concert is in Stockholm Sweden in December.  In the US, the show is coming to Chicago in March.

Both concerts really appeal to me, and I would love to go to both.  We’ll see.  I would need to take a half a day off of work, at least, to get to VGL in Ft. Wayne.  It is on a Friday night, while Distant Worlds is on a Saturday.

What is your favorite soundtrack?  Video game?  Movie?  Would anyone else reading this consider attending a VGL concert?

After the closing of MCPR, a group of us entered negotiations with MT Business Technologies, a company whose services are in great demand in the area. After a few short days, we have come to an amicable opportunity. As of today, I have begun working at the company. While I can’t give a lot of detail, for confidentiality reasons, I will say that I am starting by helping the Sales Support staff with their workload, learning to write specifications, scope of work, and other related documents, in MT’s preferred fashion.

I hope to expand into new territories and help the company become even more profitable than it already has become, and I look forward to many years of opportunity to exercise my current and growing skillset.

For the most part, I would like to spend the time answering anyone’s Linux questions. But I thought I would include some weekly news, and I want to include two applications per week, one graphical and one text-based.

To get help with any conundrums, email len@nosbig.net. I want to hear from people before and during the podcast. I will probably post the rehearsal after I edit it down a little. There were a few spots where my ADD got the best of me and I repeated myself or I had to pause a moment to collect my thoughts. I thought I had prepared sufficiently for this episode, but clearly not.

• Obtaining and reflashing a Linksys WRT54G router, either the GL or GS.
• Playing with and/or hacking a LaFonera wireless access point
• Building my power lockout device for my ham radio
• Building a PC for my car with wireless capability for a media center
• Building a decent amateur radio station, including packet station
• Building a podcast station
• Upgrade my radio license to General Class

At some point in the future, I want to do some kind of podcast. But before I would commit to that, I need to find a topic that I can regularly update and contribute. Part of the issue of the lack of updates is the company for which I work. MCPR has me doing some very interesting things, but they are marketable ideas that I have to keep quiet. The only project that I can talk about is our Asterisk dabblings. We are offering the ability to connect analog or IP phones to the system and connect to about any outbound media out there, including SIP trunks.

But much beyond that, I don’t have the ability to talk about the details of what I do at work with the world at large, between protecting our clients’ privacy and not wanting to give any competitors any ideas about our strategy.

There has been quite a bit of life to have happened in the time I have been away from this site.

First, I moved out of the childhood home into an apartment in a neighboring town… The move has been a positive one overall, but I am learning just how much more work living on my own is.

Second, I have changed employment once again. I would prefer for this to be my last move on that for a while. I left Radio Shack to pursue the opportunity of Geek Squad, and when that didn’t result in what I wanted, I was lucky enough to find my current full time position at Staples.

Third, I have had the joy of knowing a sugar glider or two in my lifetime. A few short weeks ago, Bianca brought home a sugar glider. Sasuke, a young boy, was a happy and healthy glider. About a week later, I brought Sakura, my baby girl, home to be my pet and to breed a couple more gliders with Sasuke. A week and a half ago, we found Sasuke in the bottom of the cage, curled up in a ball. He would occasionally spend time sleeping in the bottom corner of the cage. When we went to nudge him and wake him up, he was stiff. I was a little upset over his absence since then, but Sakura has been bonding quite well with me. Even last night, she took only about three minutes to pop her little head out of her travel pouch and onto my chest. As of tonight, she is no longer with us. Sakura died as mysteriously as her friend. Bianca told me that she had been found on the bottom of the cage, motionless.

I was not too fond of the idea of a sugar glider at first, but they really are cute and social creatures. I hope to get another one day, and I hope to learn more about them so that the new ones can live longer than Sasuke and Sakura did.

Finally, I have a wonderful girlfriend of over one year. She has been able to make me see parts of myself that I would not have noticed otherwise; her many unique faces make me smile, and her warm embrace just makes my day better just knowing she is there.