Jonny and the Cell (pt. 1)

My quest began, like so many others, while standing in front of my white board. I was slowly trying to identify something--something elusive--yet so simple was it that my failure to articulate it must have been born of the same difficulty one might have when trying to bring into focus the tip of one's nose, for it was its very proximity that prevented me seeing it...

Clearing the DNS cache in OS X

Every once in a great while, I find it necessary to flush my DNS cache. Usually, I only find it necessary to do this after making changes to DNS when at the office, but when attempting to diagnose some interesting Internet connectivity issues, it can occasionally come in quite handy.

I couldn't find anything obvious, but, after a moment's googling, I came across this little gem.

Anyway, here's the command:

dscacheutil -flushcache

Cheers!

Subnetting practice

I'm not sure why I haven't thought to post these before now, but here are a couple of links that may help if you're struggling with subnetting or just want to sharpen your skills.

ipcount: a handy tool for IP address allocation in OS X

If you happen to be in a position where allocating IP address blocks is a way of life, breaking up, say, a /21 into a bunch of /28's is not a difficult task--it just takes someone like me longer than I'd like.

Certifiable

I was enrolled in the Cisco Networking Academy courses in high school, and ever since, I've wanted to pick up my CCNA. Looking back, I don't know that I could have passed it at the time, but for a long while, I avoided taking the exam.

Oh, sh...

Over the course of almost three years, collectively, I've worked on some of the most bizarre, kludge-filled, impromptu networks you can imagine, and though I'm no CCIE, I've generally seen enough to know--at the very least--what not to do.

Prompt and Circumstance

On most GNU/Linux installs, I tend to setup my BASH prompt as follows:

GNS3 and OS X

Alright, if you have a Mac, completely forget a very large portion of everything I said before: there is a much better answer when it comes to setting up DynaMIPS w/ GNS3 in OS X.

First, go here: http://sourceforge.net/project/showfiles.php?group_id=160317&package_id=235898. Get Dynagen_0.11.0-Tig.dmg and, if you don't feel you need Dynagen (you don't), feel free to yank the DynaMIPS executable out of the DMG and throw it someplace useful, just as before.

Next, go here: http://www.gns3.net/download. Get the GNS3 DMG and promptly install the hell out of it.

Now, run GNS3, tell it where to find the DynaMIPS executable, download and configure an IOS image, and voila! You have yourself a shiny new DynaMIPS/GNS3 install in OS X.

Handy? Absolutely. Handier, still, on my MacBook? Oh, hell yes.

No home? No end? BWAAAH!

Comfortably using a MacBook when you're used to the PC paradigm can be a pain. As it turns out, I find that this is usually due to the little differences: directory structures, icon locations, naming conventions, etc. However, the most important thing, for me, is whether or not I have proper command of my keyboard. Home? End? (The real) Delete? Where in the hell are they?

Speaking of wi-fi...

If you happen to be using OS X, eventually you'll wonder why in the hell you can't observe the SNR, RSSI, or channel of any access points, connected or otherwise. What's more, if you're familiar with iwconfig under GNU/Linux, you'll probably want something that works from a terminal session. Well, it turns out that just such a tool has already been provided; it just takes a fair amount of searching and a small amount of setup to start using it.

Wi-Fi and Chai

Free wi-fi and a cup of vanilla chai make up a favorite combination of mine. Though I hold no particular allegiance to any one, local cafè, I do tend to spend most of my time at Aroma. I think that has a great deal to do with my old friend, Brian, who left the area a couple years back to pursue his dream of breaking into the professional CG industry (e.g. Pixar). He used to spend a great deal of his time here (I'm in Aroma, now), laboring over his latest creation. Well, to make a long story short, I guess his fondness for the place rubbed off on me, and--well--here I am.

Silence Is Golden

When I first inherited my new MacBook--and I am forever grateful, might I add--it came with some very nasty fan noise. It turns out that some Geek Squad reject took something blunt and heavy to the top of the keyboard and smashed the underlying metal into the fan. Luckily, a quick stop by the Apple shop on campus and a few days away on a camping trip cured all of my fan woes--and at no cost to me, at that.

Now, it's quiet as can be: no more propping one corner up with a guitar pick or shuffling papers on my desk, a la Jenga. It truly is a beautiful thing.

Ssshh... Can you hear that?

...I didn't think so.

An aside

By the by, if you need a multi-protocol IM client for OS X, Adium is very sexy. I just have to keep staring at it, hoping wistfully that someone will find their way online and message me. I feel compelled to type things in it and watch it post messages for purely aesthetic reasons. Seriously, it looks great.

DynaMIPS + GNS3

I'm currently studying for my CCNA. I had put it on hold for some time, but recently decided that I was tired of not having it, despite my experience in the area. Having heard about the Cisco router emulator, DynaMIPS, from a couple of my coworkers, I decided it was time to give it a spin. After all, my two 2600 series routers are fine for setting up routing protocols, but if you want a real topology--specifically, a mesh--then you need a minimum of three routers, and more is better if you're practicing redistributing routes.