Monthly Archives: April 2010

BrainDeadTip

CCNA certified

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Well, it took me long enough to get my ass in gear to do it – but I finally got around to taking the CCNA – and passed on the first attempt.

I’d been planning on doing so for as far back as my last few years in commercial radio, but a level of uncertainty (“What exactly is ON the exam?”) led to my procrastination.

Eventually I came upon the non-credit offering brochure of my local community college, and found they offered a class on what one needs to know and study to pass the CCNA.

The course was fast paced and had an impressive instructor (smart, rarely drifted off topic, had good studying suggestions, and a pretty good sense of humor). It also included a number of materials: Lab manuals, Cisco Certified Network Associate Study Guide (ISBN: 0470110082) by Todd Lamlee, and copies of RouterSim Network Visualizer 6.0 and CertSim. (There was plenty of hands-on lab time as well, including two Saturday workshops).

The  Network Visualizer software  is nice when away from the classroom lab – although I quickly found that I preferred using my home lab instead (something I’d pieced together via ebay over time).

A 2950, 2 1751's, a 26xx (and 2 2900's not pictured)

The home lab consists of a random number of bits: 2 1751’s with T1 CSU/DSU’s (got at a price of $39.00 together off Ebay), a 26xx ($60.00 off Ebay), 2 Cisco 2900XL’s (appx $70 together from Ebay), a 2950XL (about $80.00 off Ebay), 2 Quagga routers, an ImageStream Rebel Router, and a server dedicated to virtual servers (which I used to emulate 7204’s via Dynamips). Yes, a lot of the equipment is old, but it works great.

By the way – you CAN connect the T1 WICs back to back using a T1 crossover cable. Many other types of cards (ADSL cards for instance) don’t allow you to do this.

A T1 crossover cable (Integrated or external CSU/DSU is required)

When away from the house, I quickly become fond of  Dynamips (a Cisco Router emulator based off of QEMU). Only after the exam did I learn the beauty of GNS3, a great front-end for Dynamips that allows one to lay out a network graphically. (Which saves a lot of time as I was previously building everything by hand).

GNS3 - making network simulation easy

When using GNS3, I personally recommend also using PuttyCM to enjoy the use of tabbed Putty connections to your simulated equipment. I believe a youtube video from Train Signal is what ledme to PuttyCM (although it appears they may have been using something slightly different):

This is PuttyCM

As I mentioned, the course provided a few decent pieces of software – the first being Network Visualizer. The biggest pro to Network Visualizer is that it doesn’t require a copy of an IOS image to run a simulated router. It does cause CPU to ramp at times (of course Dynamips does the same thing emulating a device), and it is limited in IOS commands, but for an introductory piece of software, it’s not bad.

This is RouterSim

The real beauty in the RouterSim Suite is CertSim. CertSim is almost the exact same experience one has at taking the actual exam. I’m not sure how many questions are in the CertSim question bank, I only ever came across a very very small number of Simlets though. I should disclose that I actually worked with CertSim for about a day, as I’d not realized I had it:

A realistic simulation of what the CCNA exam is like.

Having plenty of PTO to burn, in the end I decided to schedule my exam on a Monday, and take off the previous Friday. 3 days of nothing but studying (well, I took  breaks here and there to play with my latest toy and grab more coffee) and Monday I got the cert.

Next up? The first of 3 exams for the CCNP.

RF, What?!, Wireless

New Wireless Toy

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I’ve really been enjoying the feedback on the free wireless access from my neighbors. As always, everytime I start a new hobby, I end up with a handful of new toys – and I got one just today:

The Wi-Spy 2.4x

The Wi-Spy 2.4x is a portable USB spectrum analyzer for the 2.4Ghz range (They have other models that cover 900mhz and 2.4/5Ghz). The 2.4x model includes an external antenna (SMA), whereas the 2.4i has an internal antenna only.

The Accompanying Chanalyzer software

With the use of a wireless card, one can overlay SSID’s atop the channels in the Topographical  graph and determine what radiation  belongs to which Access Point. The bottom graph (Planar view) allows one to view which Zigbee channel, wifi channel, or frequency range is most in use.

There’s a similar device on the market which is substantially cheaper, the Airview,  manufactured by Ubiquiti Networks (~$39 vs. ~$160), but from what I’ve seen, the Chanalyzer sofware in use with the Wi-Spy appears to have more features (the ability to record your captures, the ability to overlay RF “fingerprints” of various devices atop your captures), etc. The Airview software is written in Java (Read:  supported in Linux), whereas Chanalyzer is written in .NET (good luck with that one under WINE).

There are Linux tools for use with the Wi-Spy (Spectrum-Tools) which I can defnitely appreciate,  but again the recording/playback and fingerprinting along with SSID overlays really make Chanalyzer nice. (For the record, you can actually record the data using one of the tools in the Spectrum Tools suite… I don’t believe you can playback easily though)

Spectrum Tools: from the author of Kismet

I’m supposed to be working on a number of other things at the moment (studying for an exam being the major item on my to-do list) so unfortunately this post is more of a “guess what I just got” as opposed to a “look at what this can do”.  In the next few weeks, I plan on picking up an AirView also, and will provide a side-by-side comparison of the two.

In the meantime, check out this video advertising the Wi-Spy, and if you have any experience, recommendations or thoughts on it or the AirView – hit me up in the comments.

Engenius, RF, Wireless, WRT-54G

A New Look for Wireless

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I’ve done quite a bit in the past few months with the neighborhood wireless project.

First off, I’ve moved everything from the Linksys WRT-54GTM devices to an Engenius EOC-2610. The system Atheros AR2315 based. (More pictures here)

An Engenious Naked. Totally hot.

The firmware is still OpenWRT kamikazee (I dumped DD-WRT a while ago on the 54G’s), with a patched version of the NoDogSplash captive portal  (to prevent the graceful exit when a null token is submitted, also to support a “Magic token”, since I don’t truly care about it being the same one issued during the pre-authentication phase).

The only lingering issue relates to my version of the hardware not handling a reboot, which is a known issue apparently related to the kernel’s watchdog driver. There’s already a patch out there, and I plan on implementing it soon. (At present, an “init 6” will simply cause the unit to stop responding – requiring an actual powercycling) The good news is that I’ve never had to actually reboot the device for any reason.

Other installed packages include NProbe for Netflow export and  SNMP for monitoring/graphing purposes. In all honesty, the build is rather simple but effective. It’s also waterproof – the Engenius EOC-2610 is built for outdoor use – complete with waterproof housing and PoE support (albeit based on the warnings on the PoE injector, I don’t believe it’s 802.3a[ft] compatible)

As of this morning, we’re up to 13 users in the neighborhood. Shortly, I’ll be lighting up the Eastern portion of the neighborhood, which will provide access to a larger number of users.

Oh, and there’s a new look to the portal:

The new Midtown WiFi Theme

The new look is a slight modification to the Lorea Hub Theme, with additional imagery from istockphoto.com.

What?!

Music: Ripping and Audioscrobbling

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I’m a big fan of Last.fm – a social networking site that allows you to stream audio and share your music interests with others.

The LastFM Social Site

You may have noticed the inclusion of my recently listened to tracks on the bottom right side of this screen:

My recently listened to songs.

One of the major benefits to LastFM is it’s API – instead of being tied down to using only the LastFM player to ‘scrobble, I can use pretty much any open-source audio player I want  – and still share my recent tracklist with others. (Googling “pandora API” reveals that as of a few months ago,  Pandora has yet to release an API)

The LastFM player

The open API has allowed a number of really nice applications to be developed – you can AudioScrobble from an IPhone, a BlackBerry, graph your listened-to artists history, etc, etc…

Personally, my most commonly used item is one of the most minimal: an MPlayer CLI wrapper used in conjunction with LastFMSubmitD. This allows me to run my player behind a screen and ‘scrobble at the same time. (And running the player behind a screen gives me the freedom to bounce in and out of X)

MPlayer behind a Screen

Over the years, I’ve been slowly working on digitizing all of my audio library. Initially, I was doing the process using only LAME (especially since I generally prefer a command-line tool for most things), however not having anything to add the ID tags to tracks, I finally migrated to using GRip.

Grip and the Velvet Undergound

Grip allows you to set whatever format string for filenames you want, handles the CDDB lookups and automates ID3 tagging. I generally don’t use the audio player, but it’s there also.

My overall goal is to install an outdoor speaker system in the next few weeks and have my WebpadDT streaming my entire audio library over the wireless from a control point in the kitchen.  The Webpad is ready, the library is 1/3 ripped, now it’s time to find some good speakers.