These IP network blocks were set aside for private use (for testing networks) and don’t appear on any (properly configured) public network. This makes them ideal for use on home networks or internal corporate LANs *.
Class A: 10.0.0.0 (Up to 16,581,373 individual IP addresses)
Class B: 172.16.0.0 (Up to 65,023 individual IP addresses)
Class C: 192.168.0.0 through 192.168.255.0 (Up to 255 individual addresses.)
The Class C block is actually a set of 255 Class C networks. 192.168.0.0, 192.168.1.0, 192.168.2.0 and so on. Only the last octet is used for an individual host (computer, router, etc), the other three are used to specify the network address.
All of these blocks can be subdivided (or “subnetted”) by using a subnet mask. The “default” subnet mask includes only the network portion of the address. So for 10.0.0.0,the default mask would be 255.0.0.0. But you could use something like 255.255.0.0 to break it up into 255 small networks, each of which would have, at most, 65,023 (that’s 255 x 255 – 2) hosts on it.
A curious reader may wonder, “Why is it 255 x 255 – 2? Why not the whole 255 x 255?”
That’s because one address on each network (the one where the host bits are set to 0, e.g. 10.10.0.0) is reserved as the “network address” and another one (where host bits are set to all 1s, e.g. 10.10.255.255) is reserved as the “broadcast” address.
*You should almost always (some corporate settings are excepted) set up your private network to use one of the network blocks discussed here. Setting up your private LAN so that it uses other people’s IP addresses would have the effect of hiding the other poeple’s web sites and such. (For example, if your home network used the 72.232.101.0 network, you wouldn’t be able to reach WordPress.com, and what fun would that be?) Setting up a public network using someone else’s IP block would likely get you into trouble with whoever was providing your Internet connectivity. Don’t do it.
Monthly Archives: January 2008
Performance Appraisal
When you fill out the self-evaluation portion of your annual performance appraisal, you’re supposed to be honest. I had to do mine a couple months ago:
Q: List what you have done with respect to your job that provided the most satisfaction during the evaluation period.
A: I got paid.
Q: List what you have done with respect to your job that provided the least satisfaction during the evaluation period.
A: Arrived at the office after sitting in traffic.
Q: List any improvements that you believe can be made in your own performance, your work environment, or in areas where you feel [the company] could make changes.
A: Pay me to stay home.
I wonder if it’s possible to be too honest on these things.
If Pigs had Wings…
When I brought in the mail on Tuesday, I found a largish envelope with the name Squish on the return address. So right away I knew something interesting was afoot.
Squish is one of the many colorful characters populating my world. Lots of people refer to her by her nickname of “Amy,” but I’ve long found the sobriquet “Squish” to fit her well.
When we first met, Squish’s job title was GUI Engineer which meant she worked on (among other things) creating web pages. In the unique language of computer geeks, the acronym GUI (short for “Graphical User Interface”) is usually pronounced “Gooey.” Naturally (and somewhat inevitably), this eventually led us to a deep philosophical exchange on the topic of what the requirements might be for becoming a Squishy Engineer. For example, could you qualify by walking through a puddle while wearing sneakers?
So when Squish unexpectedly sends me a package, it’s immediately clear that something silly is about to happen.
I wasn’t disappointed. When I opened it, the package contained a Pig Catapult and a New Mexico UFO operating license.
Now the UFO operating license makes all sorts of sense. The authorities tend to take a very dim view of unlicensed pilots, so it’s good to have that legality taken care of.
But the pig catapult took me off guard. Why is it that a pig catapult would make Squish think of me?
When I asked her, Squish replied, “Who ELSE do you know who might ever use a pig launcher??”
She has a point. And as a bonus, I’m now prepared for the next time someone tells me something will happen, “…when pigs fly!”
Dead Battery
My car – a Honda Civic Hybrid – costs more than one with a conventional engine. To help make up for the the extra cost, the manufacturer included a few extras from the nicer trim package as standard items: in-dash CD player, power windows, power locks, power mirrors, and so on.
Tuesday, for the second time in three months, I found myself pondering the irony that despite all those little add-ons, the one feature I personally seem to need is a buzzer to let me know when I’ve left the headlights on again.
Pass this along to all your friends
It’s been a bit more than five months since my requests that folks stop forwarding chain letters. John was quick to echo the request. And now, a columnist with The Saint Petersburg Times is likewise requesting that people stop forwarding junk to him.
Hopefully the movement will catch on.
National ID Cards
DDMD recently noted concerns about the so-called “REAL ID” card.
(Normally I’d reply on his blog rather than posting something here, but that would require setting up a LiveJournal account and I need one more web site requiring a userid/password and nosy personal information in exactly the same way I need a hole in my head.)
Dave’s main concern is that people living overseas wouldn’t be able to get these licenses before the May ’08 deadline. That really shouldn’t be a problem since a valid US passport is one of the alternative IDs the TSA will accept and if you’re living overseas, odds are that you already have a passport. 🙂
What I personally find alarming about the REAL ID act is this little snippet from the article:
But Chertoff, as he revealed final details of the REAL ID Act, said that where a particular state doesn’t seek a waiver, its residents will have to use a passport or a newly created federal passport card if they want to avoid a vigorous secondary screening at airport security.
So you can either get a state-issued passport in the form of the unfunded REAL ID driver’s license, or you can get a federally-provided passport card.
I recall learning in my High School Social Studies class how people in Russia and China were required to have special passports in order to travel within their own countries. How glorious to live in a country like the US where nonsensical rules like that would never be put it into place. (Friends who have immigrated from China and Russia are amazed to hear stories like that. They’ve never experienced anything of the sort. Not until now anyhow.)
So under the guise of “National Security”, Emperor Bush and pals are forcing the citizenry of the US to adopt a system that 25 years ago we were being told only an evil dictatorship would use.
I feel so much more secure now.
(Grrr. Now I’m all agitated. This is my second posting under the Rants category in just three days. I usually avoid writing about politics because all it accomplishes is to make me grumpy.)
Time to Panic
I’ve run across the term “Kernel Panic” a few times, but was never completely certain what it meant. When I finally looked it up, I learned that a “kernel panic” is what happens when a Linux computer encounters an error it can’t recover from. In essence, it’s the Linux version of the famed “Blue Screen of Death.”
I also found a screenshot. Is it just me? Or does that look like the eye of Sauron staring out of the screen?
Finding out that Sauron lives inside your computer certainly sounds like a reason to panic!
(Public domain image, courtesy of Wikipedia.)
Disappointed by Honda
I like my Honda Civic, it’s been a great little car, every bit as reliable as my old pickup, and the gas mileage (46 MPG) is nothing short of amazing. But I don’t think I’ll buy another one. The problem isn’t the car, it’s the company.
Because I drive a hybrid, I’m stuck going to the dealership for my oil changes. I’m certain pretty much anyone (even me) could do the oil change, and for quite a bit less than the $50-60 Honda charges, but the dealership is the only place I’ve been able to find the specific synthetic oil I need. (10W-30 is easy to find, even as a synthetic, but good luck finding 0W-20!!)
The problem is, for the past four years, the local dealership’s version of an “express oil change” has been a pretty consistent 1 1/2 to 2 hours. (I’ve more than once fell asleep waiting for them. One time, after 90 minutes, I discovered I’d forgotten to give them the key – they never noticed!) Couple that with completely failing to follow-through when I’ve left complaints for the service manager and it becomes clear that this is not an organization that’s overly concerned about customer satisfaction. (I’ve never received an apology, but they do send letters periodically suggesting I buy another car from them.)
A week or so back, the check engine light came on. Between hybrids being slightly different from most cars and the fact that it was almost time for another oil change, I decided to take my car to the dealership. Not the one here in town, but one just a mile or two from my office.
They repaired the car just fine, I’ll give them that much. Then they claimed to have had problems starting it and suggested I should buy a new battery. The only time I’ve had trouble starting the car was when I left the headlights on. Taking it to the dealership that morning, it started up no problem, and again with no difficulty when I picked it up in the evening. Still, I’m one of the vanishingly few people who know how to drive a manual transmission, so I wrote off the problem with not starting as someone who just wasn’t familiar with manual transmissions. Now I’m not so sure. Maybe they really were trying to sell an unneeded repair.
Running errands this morning, I noticed a yellow sticker inside the frame for the driver’s door. Unless I want to know the correct tire pressure, I don’t pay a lot of attention to doorframe stickers, but this one caught my eye. Taking a closer look, it turned out to be from the dealership that did the repairs, with the phone numbers for the sales and service departments. In short, they put an ad on my car.
I don’t wear T-shirts with company names on them. If Nike, Adidas, or some other apparel company wants me to wear an ad for their product, I feel they should at the very least give me the shirt for free. No way am I going to pay for someone else’s ad. And that’s essentially what’s happened here, the Honda dealership has put me in the position of paying for the “privilege” of having them slap an ad on my car.
If I were to go to the Honda dealership and put stickers on the cars in the lot (even on the doorframe), it’s a pretty safe bet that the police would become involved. So why is it OK for a Honda dealership to slap an ad on my car?
Update: Monday January 14.
The service manager at the dealership that put the ad on my car returned my call this morning. After his crew removed the sticker, he apologized and promised to put a note in the shop’s records to not do that again. But because the ad wasn’t visible to the general public, he doesn’t think they did anything wrong.
But he didn’t argue that it would be wrong for me to treat their cars the same way.
Telepresence, vacuum cleaners, and good-looking aliens
There was an episode (maybe a few) of Deep Space Nine a while back which featured a holographic communications system. The people participating in the communication would each sit in a chair within the bounds of the device (re-inventing the open-air phone booth I suppose) and would be able to see and talk to each other as if they were sitting across a coffee table.
That doesn’t exist quite yet. Ditto for the transporter room, faster-than-light travel and the sexy aliens. (That’s not quite true. The sexy aliens may very well exist, but we haven’t met them yet. Not officially anyhow.)
I’ve been intrigued by the iRobot Roomba for a while now. Roomba is essentially a robotic vacuum cleaner. It’s not as talented as Rosie from the Jetsons, but the idea of having the vacuuming “just happen” without any effort on my part is very appealing. (I’m a guy. Having a robot do the vacuuming would greatly increase the odds of it happening.)
Checking out the iRobot website this evening, I discovered they have a new robot. Along with the vacuum cleaner, the pool cleaner, and the gutter cleaner, they now have a “Virtual Visiting Robot” which apparently uses a combination of robotics, VOIP, and streaming video to allow to you interact with your family when you’re away from home. (It occurs that you could also send this along when the family went out of town and you had to work over the weekend, but that would be a clear-cut case of mis-applied technology and a pretty good reason to find a new job if your boss ever suggests such a thing.)
It’s not quite the holographic communication system, but it’s certainly a step in the right direction.
Also intriguing – and in the words of Dave Barry, I swear I’m not making this up – is the robot they created in a partnership with John Deere: the “R-Gator.” This is essentially a John Deere Gator (you’ve perhaps seen them used at parks and zoos, sort of a heavy-utility all-terrain version of a golf cart), but outfitted with robotic systems so it can drive itself.
The R-Gator is also described as an “Unmanned Ground Vehicle” and appears to only be available for Government/Military use. The aforementioned Roomba starts its vacuum-cleaning cycle by moving in an expanding circular path as it seeks out dirt. I can’t help thinking that the ‘R’ in “R-Gator” perhaps stands for “Roomba.” Maybe the Roomba-gator starts out all of its missions by also moving in a circular pattern. (On the scarier end of the spectrum, according to one report, during an early phase of their development, the machine gun-toting “SWORDS” military robots had “a tendency to spin out of control from time to time.” So perhaps the idea of military robots based on Roomba isn’t so far-fetched after all!)
So iRobot is doing a pretty good job of fulfilling some predictions of the future:
- …a precursor to Rosie. check
- …telepresence like Deep Space Nine (all that’s missing is the holograph). check
- …military robots like the ones in the Terminator movies. check (shudder)
Hey, wait a second! Where are the sexy aliens?
Nuts. What kind of a future is this anyhow?
Happiness is a Warm Puppy
The Washington Post had an “online extra” today about the dos and do nots of keeping pets warm in the winter months. One of the warnings was about the dangers of giving your pets a heating pad – they might not notice that they’re getting burned.
The article also mentions the fad of putting sweaters on pets. Apparently there actually is a benefit to it for some pets, but it’s best to avoid synthetics as they might cause static electric shocks.
Also, if you make your dog or cat wear sweaters, all the other pets will laugh at him.