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 have been using the tablet off and on since then, with most of the functionality available while logged in, but there have been a few rough edges.  With a tablet PC, how do I log into the tablet while it is undocked from the keyboard?  I have used a great on-screen keyboard/handwriting recognition tool called Cellwriter.  It requires a little training, but the tool is very accurate after training.  There are two instances where a user needs to enter a password, when logging in and when unlocking the screensaver.

• Login: I use Gnome, so GDM is the login manager I prefer on this tablet.  Changing the configuration was fairly wasy.  The configuration file, in Debian, is /etc/gdm/Init/Default.  I found that a single line, added above the final “exit 0″ line, was enough to add the keyboard: “cellwriter –keyboard-only –window-x 170 –window-y 568 &” and restart X by logging out.

• Screensaver: The screensaver was slightly more difficult, requiring two steps to configure within gconf-editor:

1. Enable the embedded_keyboard_enabled key in /apps/gnome-screensaver.
2. Edit the embeddes_keyboard_command to include: /usr/bin/cellwriter –keyboard-only –xid

I could have chosen one of a number of alternative keyboards, but Cellwriter works so well and looks so clean compared to the other tools I had tried.  There are two issues that I have been dealing with with little success…

First, the –keyboard-only flag is in both locations to run the keyboard without regards to the written input.  I expected to need that during login, as GDM has idea who is logging on until after they have logged on and GDM is no longer needed.  However, I did try to use it normally with the screensaver login, and I could not get gnome-screensaver to accept my known-good password while using the handwriting portion of the application.  While I would like to be able to write my password, your entire password remains on the screen in the input box until you accept the input.  So, I will try to get at working sometime, but it probably better that i have to type my password, keeping it hidden from view.

Second, each of the applications would randomly spam one of the input buttons as I was typing on the screen.  This forces me to have to simply hit the enter key and start again.  At some point, I will have to try using the native fpit driver within Xorg.  I might already be, now that I have upgraded my system to the post-Lenny testing version of Debian (Squeeze).  I haven’t otherwise updated the system’s overall configuration in several months.

So, hopefully, I can start getting even more utility out of this again, without the encumberance of this keyboard.  As much as I would like to try one of the new netbooks, like the Acer Aspire Once or the HP Mini 1000, the lack of a touch screen makes those devices a less-attractive form-factor that this handy piece of gear.

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.

I agree with Chris that competition for Windows is a good thing…  Particular because Windows market share is eroded in the process.  I work in an IT shop every day where the architecture of Windows and its 20-year legacy cause endless issues with clients.  Much of the problem revolves around third-party applications being written to an old or incomplete specification.  But I digress…

The following items are misconceptions which, like bad email hoaxes, never seem to go away:

1. Kernel Compilation: Please do not believe that you have to compile your own kernel.  For nearly every distribution out there, the kernel probably supports 99% of the hardware in any given system.  The more high-profile a component is, the higher chance it will be supported.  If you choose to purchase (for example) a cheap $30 widget that is found in the clearance bin in your local electronics store, you might have some problems.  While there may be a Windows driver, it might be hard to find a replacement driver if you lose the CD it came with.  For SATA controllers, CPU’s, webcams, digital cameras, printers, and more, the Linux kernel provides the drivers.  Also, the folks at various distributions work very hard to package the kernel to interact nicely with the rest of the system.  As an example to the hardware argument, I will discuss my laptop.  I purchased a Lenovo z61m (Intel Core 2 Duo, 1GB RAM, SATA HDD, Intel video and wireless, Fingerprint reader, etc).  Without recompiling my kernel, I have used all of the internal system components as well as a bluetooth adapter (Kensington), digital camera (Sony T1), webcam (Logitech STX), a Nintendo Wii Remote, Wireless presenter remote, external mouse and keyboard.  The only piece of hardware which does not work completely is the memory card reader.  The SD portion works, but the xD portion (which I do not use) has no driver available for this device.
2. Linux Installation: Again, Ubuntu has been a shining example as to how easy a Linux distribution is to install.  Fedora, SuSE, and Debian are not that far behind.  In fact, modern Linux distributions are better than Windows during the installation at finding drivers for hardware.  I have had more hardware missing drivers with a freshly-restored system (from the restore partition) of an HP or Gateway laptop than from any of the last ten or so Linux installations.  To me, the lack of proper hardware support (at least for the network adapters, to enable the retrieval of additional drivers) is rather disturbing.  As an aside, the old argument stands in many ways.  The overwhelming majority of computer users already have a system administrator to manage or install the operating system (company IT, “that kid who knows computers”, groups like Geek Squad, etc.).  While I appreciate the desire for an easier install, I also would mention that Windows users have learned as much about their operating system as Linux users have about theirs (from a systems administration perspective).
3. Linux Support: The age-old question of how to get support for Linux…  First of all, see above.  Most people (regardless of operating system) seek advice from someone “smarter with computers” than they are.  For those folks who appreciate the technology and have learned more than the basics, what do you do when you have a problem?  That’s right, you turn to Google, discussion forums, and the user community.  Guess what?  Linux has many of the same support structures.  Countless how-to sites, forums, chat rooms, blogs, and e-mail mailing lists (all indexed by your favorite search engine) provide an insight into the solutions to a given problem.  In addition, Linux can often add a layer of community support which Windows users have seemed to have left behind, the User Group.  Across the globe, thousands of Linux user groups meet (weekly, monthly, or annually) to discuss new technologies, new software, the community itself, and supporting each other.  One item that tends to put some people off, however, is the attitude of some communities to new users.  All most of those communities ask is to invest something in your own problem.  Often, new users will enter a support forum and ask, “How do I get “foo” to work?”  While that question isn’t a bad one, it reveals to the community that this person has not even run a single Google search to have an idea where to start.  If the same user were to ask, “How do I get ‘foo’ to work?  I have seen that I have to look at my syslog, but I’m new at this and don’t know where to start,” the response will often be warmer.  Of course, if someone would insist on some hand-holding and cannot afford to spend some time learning, then they should pay a support provider (Red Hat, Canonical, Novell, or a member of a local LUG) to provide that assistance.
4. Application Compatibility: This one has got to stop… now.  Let’s examine Windows.  Should someone need an application which is native to Windows, you just grab it and install it.  What if you want to run Linux/UNIX software on the machine?  or Macintosh?  Cygwin is a product which provides much of the support to run Linux/UNIX command-line and graphical applications on Windows.  It is free and open-source and maintained by Red Hat.  Or one would find cross-platform support.  Some of our favorite tools in the community on Windows are cross platform.  Firefox, Pidgin, Gimp, and OpenOffice.org come to mind.  Of course, all of these will work on Windows and Mac, in addition to Linux.  To compare, the same tactic can be applied to running Windows applications on Linux using Wine.  Of course, the ultimate solution for the best compatibility is to run the tool in its native operating system.  With the advent of free virtualization software, anyone can run the operating system of their choice as a virtual machine.

With all that being said, I believe open-source software (with Linux having lead the charge) has won and will continue to push aside proprietary software.  We see (or more importantly don’t see) Linux in all sorts of places.  Early usages of Linux in a commercial environment (e.g. TiVo) provided a catalyst by which Linux began to be used elsewhere.  From web servers to routers to search engines, Linux is everywhere we go today.  With the quirks of the Windows operating system, its no wonder that people are flocking to OS X.  Never mind that users are trading one proprietary software company for a proprietary system company…  Ultimately, the open nature of the software I choose to use everyday enables a better life for myself and those around me, and I couldn’t imagine living with the shackles of Microsoft restraining me from making the technology do what I wish.

[display_podcast]

This episode includes the following products, websites, OSS projects, and organizations:

• Ohio LinuxFest: The premiere fall Linux event for Ohio, the Midwest, and beyond
• LPI: World’s most well-known vendor neutral certification and advocacy organization
• Don Corbett: Linux training and consulting
• ZenOSS: Open Source Configuration Management and Discovery
• MythTV: Overall DVR, home entertainment system
• Jon “maddog” Hall: Executive Director, Linux Foundation
• Drew Curtis, Fark: Founder, Fark.com
• Microsoft and Yahoo deal: CNet news.com
• Zimbra: Open-source Exchange alternative, mail server and collaboration suite
• Office Open XML Format Wars: Groklaw.com
• Microsoft ISO Vote Tampering: Computerworld.com
• WordPress 2.5.1 Release: Blog-ish Content Management System
• iRiver Clix gen2: iRiver America product page
• iRiver Clix gen2: Amazon.com bundle
• Amarok: KDE’s media player
• RhythmBox: Gnome’s default media player
• gPodder: Awesome light-weight podcatching client
• NCOLUG: the North Central Ohio Linux Users’ Group

As usual, I want to hear from you! Send your feedback to:

len@nosbig.net or leave feedback on our voicemail box at (206) 350-8405.

Podcast theme music provided by Mark Blasco, www.podcastthemes.com.

Two of the most enjoyable talks I have seen so far have been from two very different scientists with two very different interests.

Jill Taylor, a neuroanatomist from Boston, talks about what it is like to have a stroke, from personal experience.

Cliff Stoll is most famous for catching some international espionage agents through computer forensics and network security, but he really enjoys physics, astronomy, and education.

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?