I lost 30 pounds in three months. If you wanted to know how I did it, and how I intend on maintaining my current weight, then these 50 weight loss tips are for you. I’m not an expert, but I do speak from experience. If it helps you attain your own weight loss goals, then I’m happy to have helped (if only to serve as a reinforcement of knowledge you already possess). Most of this, I learned on my own or through close friends and family members. Feel free to add your own tips to this list, too!
If you want even more help, I now have an PDF eBook series available (with an affiliate program): get my diet weight loss ebook before you scoot away!
1. Dietary control and exercise. It’s true what they say - all you need to do is watch what you eat, and expend more energy than you consume. It’s really that simple. You can quit reading this list now, you now know everything you need to know and didn’t need to fork over $500 for the privilege of me telling you the secret of losing weight. You don’t need to read a 4,000 page book, you don’t have to buy a tape series, you don’t need to stay up late at night to watch infomercials to understand this basic premise. It’s 100% true.
2. Change your lifestyle. If you’re calling this a “diet,” then you’re going to gain all the weight back (and more) within a few months of losing it. Diets do not work. Diets are temporary. When you change your dietary lifestyle, however, you’re changing your habits - and you’re putting yourself on track for long-term / continued success and weight maintenance. Don’t ever tell anybody you’re on a diet - ever. I’m speaking from experience, here - a reformed low-carber. Worked out well for a while, but ultimately failed because my entire lifestyle didn’t change (permanently).
3. Join an online support group. In my case, I created my own - FatBlasters. It’s essential that you not feel alone, and reaching out to friends (new or old) is typically a smart move. I just heard about PeetTrainer, but didn’t know about it when I began down the road to weight loss. You have to know that others are out there for moral support - they know things that you couldn’t possibly know, and they’ve probably been “in your shoes” at some point in the past (or present). Share stories, laughter, tears, successes, and failures - share them. There are thousands of communities out there, so keep looking until you find the one that fits you.
4. Take before and after photos. I know it sucks to see yourself as a chunky monkey (sorry, that’s what I called myself - if only to get myself motivated to meet my weight loss goal). However, there’s no easier way to illustrate your progress. The “after” photos are far more fun to capture and share, admittedly. Find yourself on Flickr! It’s good to see yourself how others see you. Do you like how you look? In many ways, Flickr helped me lose weight.
5. Hire a substitute teacher. Don’t reach for the brands you know and love immediately - or without thinking first. Eggs are “good” for you, but consider using egg substitutes instead (in fact, many restaurants will let you order lower calorie foods). There are countless “lower” alternatives for you to try. If something different doesn’t taste good, by all means - find a better substitute, or eat less of the original. In some cases, the substitute may be worse for you than the regular version of the product. The good news is, healthier choices are silently replacing their “normal” counterparts - and they taste just as nice.
6. Start reading labels. I know it sucks, but you have to do it - and there’s no way to avoid this tip. If you don’t know what you’re putting in your mouth, you’re flying blind. Don’t assume, either - triple-check the ingredients list and serving sizes. You must rely on yourself for this; nobody else is going to be able to lose the weight or do the math for you. It’s not that complicated a task, but it will require effort. If nothing else, just pay attention to the calorie count.
7. What’s so funny about bovines? If you like cheese, you must buy the Laughing Cow brand, and keep several of the suckers in stock at all times. The individually-wrapped wedges make for excellent snacks, and are wonderful when melted over just about anything edible. I’d be careful about straight-up American cheese, though - it’s oil, but not necessarily as good for you as (say) a slice of cheddar would be. I have yet to find something as calorie-light and filling as Laughing Cow (I don’t know how they do it).
8. Tell your family. You’re not going to lose the weight alone, even if you ARE alone in losing the weight. If you’ve got a family at home, talk to them about it - initially, not incessantly. Let them know what you’re going to do, and that you want (and need) their support. If you don’t let them know, you’re running the risk of them inadvertently sabotaging your efforts. You want them to help you get to your goal(s). You want them to share in your happiness when you’ve made it past a certain mark. Who knows? Maybe some of your new habits will rub off on them and they’ll become healthier people, too?
9. Go public. I didn’t want to admit that I had screwed up, but admitting the problem in public was the first step on the path to eventual success. I was now accountable for my actions, and all my friends knew what I was doing. There was no turning back, otherwise I’d be risk damaging my integrity. I didn’t want to disappoint the people who read me on a regular (or semi-regular) basis. Plus, it’s an easy way to find out which of your friends have gone through the process before - and glean tips from their own experiences. Then, other friends might become inspired to do the same thing you’re doing once they see that you’ve taken the first step.
10. Identify your exercise. No exercise was created equal. You might like running, so run. You might like jogging, so jog. You might like stationary bikes, so bike stationarily. Find the one that works best for you - that isn’t too much of a chore for you to do regularly throughout the week. Don’t pick a routine that you don’t like - or you won’t want to do it, and you certainly won’t stick with it for long. I also wouldn’t recommend buying into that whole “no pain, no gain” mantra. I’ve lost weight without hurting myself, and you probably can, too.
11. Become a Gazelle. You’ve probably seen Tony Little on TV, selling his Gazelle glider - a low impact exercise machine. I can tell you: it works. It’s easy on my legs, and really gives me a workout when I apply myself on it. Some people say it’s awkward to use, but I love mine - and would consider recommending no other home exercise equipment at this point. Then again, I’m a wimpy geek who only wants to burn calories.
12. Zone out. There’s a reason why people exercise to their favorite music - listening to external stimulus takes your mind off of the physical activity. That’s the secret to making “exercise time” fly. If you’re concentrating on what your body is doing, the session is going to drag on for what will seem like days. Buy a portable music player, or situate yourself in front of a television.
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13. Never count on live programming. It’s important to stimulate your mind while your body is exerting itself in other ways. However, never rely on “what’s on TV or the radio” at the time. Instead of zoning out, you’ll find yourself flipping between channels - and that’s going to make the time drag as much as it would if you weren’t keeping your mind busy in the first place. “Live” is a very bad idea. Go with pre-recorded programming or go without.
14. Video games helped me lose weight. I can keep my balance on the Gazelle (which some might find difficult to do). As such, I plugged an Xbox 360 into the TV and started to play it while I was working out. Immediately, I found that I was sweating more than I was when I was only watching TV passively! The reason boils down to a single word: adrenalin. Now, the only way I’m able to work up a sweat is when I play a fast-paced game on the game console. Yes, even game genre is important; avoid any diversions that require long pauses between tasks. Racing games (like Burnout) have worked very well for me. The more mindless the game, the better your burn, the faster the exercise session will go.
15. Set realistic goals. You can lose 50 pounds in a week if you work out 12 hours a day and eat nothing but celery - but not if you’re human. Slow and steady wins the race. Don’t bite off more than you can chew - literally. Make small goals on your way to the bigger goal(s). In the end, you’ll have achieved more (and more frequently, might I add).
16. Avoid trans fats and high fructose corn syrup. I offer this suggestion for a few reasons. First, they’re not good for you anyway. Second, you’ll eliminate a lot of the “bad foods” outright - no questions asked. You’ll have to become more selective in what you eat by avoiding these two nasty ingredients - which are in more foods than you probably care to know.
17. Don’t always listen to your mate. I’ve already suggested that you tell your family - but sometimes members of your family will try to dissuade you from trying to lose weight. It’s simple: they might not want you to succeed where they may have already failed, whether consciously or inadvertently. Your loss is not always their gain. Watch out for statements like: “You’ve lost enough weight.” or “I like you just the way you are.” Fact of the matter is, if YOU don’t like the way that YOU are - then YOU are going to have to do something about it, no matter what anybody says. They still love you, though (in theory).
18. Don’t compare yourself to others. Every body is different. It stands to reason that everybody will lose weight differently. Even if you do the exact same things that I do, you won’t lose weight at the same rate. The key is in finding your triggers. Keep your goal in sight, and do whatever you have to do to meet that goal. When you start looking at someone else’s habits, you’re only going to become discouraged and quit without even realizing that it’s physically impossible to be anybody but yourself.
19. Women aren’t men. It’s been proven that men can lose weight more rapidly than women can, which is likely due to our physiological makeup (women are supposed to have more fat than men, because they’re the birthing gender). This isn’t a sexist statement to make - it’s pretty much the truth. As such, females should expect to set separate goals than males - especially if you’re working on losing weight together, side by side.
20. Take a magic pill. Nonsense! There is no such thing as a magic pill. Don’t fall victim to the hype of the latest fat-burning drug commercial. If you listen or read closely, you’ll see that every single one of these things is effective when combined with proper diet and exercise (which they even state in their advertisements). The side-effects for these drugs are usually worse than your additional weight, anyway.
21. Vitamins are good for you. If you’re going to take any pills, let them be natural supplements (like Essential Fatty Acids or multivitamins). Be careful about overdoing it, though - especially with herbal remedies. Too much of anything is a bad thing. You can consult a nutritionist, but always buy on your own - and keep these supplements to a minimum. Remember, too, that specific vitamins are no good without specific minerals.
22. Deck your desktop. In the beginning, some of my friends sent me complicated spreadsheets to help chart progress. Uh, no - not for me; I’m the kind of guy who likes taking the easy route. As such, I scoured the Web for the best desktop tool and remembered CalorieKing. You won’t find anything easier to use. Trust me, this is the one; I can keep track of everything I eat and expend (without hassle). While the statistic-addicts will love CalorieKing for its thoroughness, the utility was truly designed with non-geeks in mind. The CalorieKing Web site and service are fine on their own, but the downloadable client is what you really want to get. Pay the registration fee, man - how much is your health worth to you?
23. Identify your ideal weight. If you’re 5′5″ with a certain build, there’s an ideal weight that matches your body type. Find it - and make that your goal. And if you don’t know what that might be, try searching the Web for a calculator (though results and calculations will vary by a small margin). Now you have a weight goal to shoot for.
24. Consider the source. I’m going to make a gross generalization here, but… why would I trust an overweight doctor or nutritionist to give me proper advice on weight loss? “Do as I say and not as I do” is not a maxim I’m willing to accept from anybody who would be qualified to tell me how to do something. Talk to people who are doing it, or who have done it and been successful. You don’t have to mirror their regimen, but at least you’re getting help from someone who’s really been there. Or, as they said in the Christmas episode of “Two and a Half Men,” people who live in fat asses shouldn’t throw waffles.
25. Ignore Ronald McDonald. You don’t have to eliminate fast food completely, but you should avoid it at all costs. Most of it is nasty, bad stuff anyway - if you’d even go as far as to call it food. If you’re looking for convenience, find a more convenient meal source. Besides, most of what they serve would be considered “food product,” not food. There’s a gigantic difference as far as your body is concerned. Your bloodstream does not have taste buds, need I remind you?
26. Scale up. If your measurement tool sucks, upgrade it. If it’s analog, dump it. I’ve talked to many geeks about their choice in scales, and most of them (myself included) recommend something in the Tanita family. They’re high-quality, rugged, accurate devices. Make sure you set your scale on a hard surface, too (as carpet foundations do not make for accurate weight measurements).
27. Watch your weight. Some people say that you shouldn’t weigh yourself more than once a week. I’ve been much happier charting my progress every day. No matter what, you need to weigh in at the same time, every time. For me, that’s 10am every morning (or somewhere thereabout). If you decide to weigh yourself every single day, understand that your weight will fluctuate by one or two pounds - and that you should only keep a serious eye on the lengthier trends.
28. One pound a week. If you’re not losing at least one pound a week on your chosen weight loss regimen, you’re (a) stalled, or (b) finished. You might need to push yourself even harder, or (in some cases) let up a little bit while your body plays catch-up. If you lose more than one pound a week, then you’re doing better than average. Expecting to lose five pounds a week just isn’t realistic, though.
29. Maintain your priorities. Sure, your sandwich would taste amazing with an extra tablespoon of mayonnaise… but do you really need it? Rather, is it more important for you to reach your weight loss goal quicker - or have this sandwich taste marginally better? What’ll happen the next time you’re faced with this decision - will you cave again? It’s a slippery slope; don’t lose sight of what’s most important to you.
30. All weight is not equal. Muscle weighs more than fat, but the last thing you want to lose is muscle! For this reason alone, it’s important to have a regular exercise routine somewhere in your schedule. Without exercise, your body is going to burn through muscle first - and you’ll wind up more imbalanced than you were to begin with. You want your body to burn fat, not muscle. You want to lose weight, but you want to lose “fat” weight - not muscle mass.
31. Counteract the “Rainy Day” principle. If you decrease your calorie count without necessarily increasing your physical activity level, your body is going to crash. It’s going to say to itself: “Holy sh*t! I better store these calories as fat, because I’m not getting enough of them - and I don’t want to die.” When you exercise, you set your body’s process to “burn” instead of “save.”
32. Don’t overdo it. If you change something in your lifestyle, you’re probably going to see results - but there’s a law of diminishing returns at play. You can exercise for an extra hour a day for a week and still lose the same amount as you had when you were only exercising half as much. Give your body time to adjust - don’t push yourself too hard or you’re just going to spend your energy on something that’s not necessarily going to give you immediate and direct benefit. This, of course, only applies to those of you wanting to lose fat - not for those who are training for a triathlon.
33. Patterns are good. Once you’ve found your workout groove, do your best to stick with it. Exercise no less than three times a week for 40 - 60 minutes each time, but don’t feel the “need” to do it more than five times over a seven day period. Your body will likely appreciate a burn-off in the morning more, but if you need to relieve stress in the evening - don’t be afraid to adjust your workout schedule accordingly. Schedule making and keeping are important for other areas of your life as well.
34. Sleep it off. To be an efficient fat-burning machine, your body requires at least eight hours of sleep a night. If you think that you’re doing yourself a favor by sleeping less, you’re mistaken. Give your body time to rest itself, both mentally and physically. Sleep is very, very important (if only for mental alertness for the following day). If you feel tired, that’s likely your body’s way of saying: “Shut your eyes, stupid!”
35. Remember that the fork is not a shovel. I eat fast (I swear I can’t help it). Even if I’m not hungry, I want to shovel everything into my mouth in less than a minute. But my brain doesn’t know that my stomach is full until twenty minutes after it actually is. As such, I could stuff myself silly before realizing I didn’t need to consume as much as I did. Try eating half of what’s on your plate, wait ten minutes, then continue to eat if you’re still hungry. You never want to feel full - ever. That’s when you know you’ve eaten too much. If you want a real hunger-stopper, try an Omega 3 and Omega 6 supplement (EFAs) twenty minutes before a meal.
36. Become your own snack fairy. It’s okay to snack between meals, really. Small meals throughout the day are enough to keep you satisfied, as (much like the sensation of being full) you never want to feel hungry. Let your body know it’s going to get a regular regimen of calories. Plus, if you starve yourself for the regular meals, you’re probably going to eat more before your brain tells your mouth to stop. Think about it: breakfast, lunch, and dinner are social constructs at their very core.
37. Love the oil companies. Just like your car needs high-quality oil, so too does your body. Not all oils were created equal, though it’s hotly contested which ones are better for you than others. Personally, I love a good olive oil - it’s 100% natural and is rich with Omega 9 fatty acids. Enova is another one that we’ve found to work quite well in our lifestyle at home. Choose your oil wisely, though - your weight loss goal should be more than simply cosmetic. It’s a good rule of thumb when it comes to food: the more natural something is, the better it is for you.
38. Fat is where it’s at. If you think you can lose weight and keep it off by avoiding all fats, you’re sadly mistaken. In fact, if you think that low fat eating is the only way to go, you might as well just quit now. Your body (and your brain) needs fat to survive! This is why the scientists call “them” essential fatty acids - Omegas 3, 6, and 9. These fats have been stripped from many supermarket shelf items, and it’s your responsibility to put fat back into your dietary plan. Don’t avoid eating fat, embrace it - equally.
39. Bring balance to the force. If you eat the same foods over and over again, you’re going to get bored - unless they’re foods you really, really like. Feel free to change it up - keep your tongue happy. Balance carbs with proteins with fats, though. If you have more of one nutrient for one meal, try more of another nutrient for the next. And for heaven’s sake, don’t just shop in the “diet” section of the store. You can still (likely) eat the same things you’ve always eaten, just not so much of them at any one time.
40. Know your daily calorie limit. When I was in the process of losing weight, it was suggested that I stay under 1700 calories a day. Knowing that number was half the battle. I could eat anything I wanted throughout the day, so long as I would stay at or beneath that number. While I couldn’t track 100% of the items I ate, I was able to make intake estimates - and adjust my schedule and ration my remaining calories accordingly. In this sense, you’re given extreme freedom - so long as you stay at or beneath that suggested calorie level for your plan. If you don’t know how much you’re supposed to take in, how are you supposed to know how much you’re supposed to take in?! Sounds redundant, but it’s a situation that many “dieters” are in (which is why they fail)!
41. Fiber good. When you start to lose fat, you’re probably going to get constipated. Yeah, it happens more frequently than we care to admit (or share). You should have a good amount of fiber every day, anyway. Fiber is very important to your health (and your weight loss goals). Try the Metamucil snack wafers for a quick fiber infusion. Then, magnesium citrate for those… “stuck” moments, in which you’ll find yourself from time to time. Stick a bottle or two of that in your fridge for safe keeping, and don’t plan on going anywhere for 24 hours after taking a dose (trust me, trust me, trust me).
42. Walk the walk. You burn calories when you walk, did you know that? Certainly, you don’t expend as much energy as you do when you run, but you burn it nonetheless. Consider picking up a good pedometer, if only to gauge how many steps you take in the average day. According to others, the Omron HJ112 Premium Pedometer is the one to beat. If nothing else, knowing how many steps you take on the average day will give you a better idea as to your regular activity level - around the home and/or the office. Plus, you can count those steps as calorie deficits in certain programs (like CalorieKing).
43. Train wrecks will happen. One of these nights, you’re going to go out with friends and eat your weight in steak (likely blowing any kind of progress you had made for that day). Instead of repeating the overindulgence, just put yourself back on track the next day. You’re allowed to “mess up” every now and again, so long as you don’t make a habit out of consuming an excessive amount of food. Right the dining injustice immediately. You’ll be okay. You’ll be fine. Just don’t do it again. And again. And again. And again.
44. Satisfy cravings with extreme prejudice. If you’re hungry for something, eat it. Don’t deny yourself the simple pleasures. If it’s possible, eat only half of what you want. Is your craving satisfied, or are you addicted to the flavor? Losing weight shouldn’t be torture for anybody. You have to ask yourself: Is it more important for me to eat this entire case of fudgesicles, or to look good for my brother’s wedding? Only you have the answer to that question, and if you ignore logic, you’re going to hurt yourself in the long-run. Just take a nibble or two - I won’t tell a soul.
45. Water you waiting for? If you’re not drinking enough water, your body will let you know. Thirst is an amazing sensation - quench it. If you’re not hydrated, your body won’t be working at peak levels. Most of your body happens to be water, by the way. If you’re worried about “water weight,” remember that you’re likely to retain more water when you’re not giving your body enough of it in the first place. Besides, that’s what those workout sessions are supposed to help with every other morning. I’m not going to dictate how many glasses you should drink, though - as that’s going to vary from person to person.
46. Join the soda club. Like most people, I love carbonated beverages. However, unlike most people, I love unflavored carbonated beverages - and if your tongue is attune to sugary-sweet drinks, you’re also the kind of person who believes that club soda tastes salty (even when it contains no sodium). Make the move to an unflavored drink sooner rather than later. If you need help along the way, lemons and limes can be your best friends. If you’re going to drink something more than water, at least make sure it’s not going to hinder your progress. If you’re a sugary-soda drinker, dropping it from your daily routine altogether will help you drop ~5 or more pounds in a single week (WITHOUT doing anything else).
47. Sugar is evil that tastes good. You probably don’t want to hear this, but sugar is a bad thing. The more refined it comes, the more your body is going to react negatively to it. Sugar, sugar, sugar is in everything, everything, everything. If it’s sweet, it’s got sugar in it. There are all sorts of sugars out there, and all of them are ultimately metabolized by the body. It’s a good bet that the sugars in an apple are better for you than the sugars in a candy bar, though. If you’re addicted to sugar, this is going to be a horrible hurdle to overcome.
48. Sugar substitutes are just as evil as sugar itself. Do you really think your body knows how to handle something that was man-made? Seriously. These chemically-adjusted products do not occur in the wild; there are no Splenda trees in warmer climates, nor are there NutraSweet plants in the Arctic. In some instances, taking in sugar substitutes may actually increase your levels of hunger! Let’s not forget about all the health issues that might arise from these unnatural substances. If you’re given a choice, it’s almost better to go with something your body knows how to deal with (real, unprocessed sugar). No, it’s much safer (and healthier) to stay away from blue, pink, and yellow packets entirely. Do a Web search for “Artificial Sweeteners May Damage Diet Efforts.” Then sit there and tell me they’re okay? No way.
49. White bread can’t jump. Did you know that white bread isn’t good for you? Oh, it’s true - just ask any diabetic. Research has shown that people who eat more refined products (like white bread) are more likely to have belly fat. Why? It’s simple: your body isn’t getting what it needs. The food industry isn’t the health industry, okay? You can’t trust that they’ve got your best interests at heart (despite all their marketing efforts). If you want the flavor of white bread, please eat the whole grain white bread instead? Sara lee makes a wonderful loaf, as I can personally attest (even though I like rye more than white or wheat). Repeat after me: whole grain white bread, whole grain white bread.
50. Hasta la pasta, baby. Much like its cousin, white bread, refined pasta can damage your health and pinch your weight loss plans. I’m not saying you should quit pasta altogether, but I will suggest that you change your pasta pusher to Barilla. They have a new wheat pasta that’s a dead ringer for the ol’ crappy white stuff you used to eat. “Barilla PLUS” is absolutely fantastic, as well as a good source of fiber and protein. You’re usually going to be better off with a “wheat” option, although traditional wheat pasta has a texture that you might not like (even though I find it perfectly acceptable to my palate).
Now, once you’ve achieved your weight loss goals, what are you going to do to keep the fat at bay? The worst thing you can do is something I’ve done countless times over: get lazy. I’ve conveniently forgotten about all of the aforementioned rules a few times, and it’s put me back in the same situation I don’t want to be in - ever again. While I don’t have to be as careful as I was during the weight loss period, I’m still measuring myself and recording my daily activities. This may turn into a weekly weigh-in soon enough, as it’s easier to correct yourself at 5lbs than it is at 50lbs. Good luck!
name knows what name server to talk to because it can get the IP address of your machine's name server from the operating system.
The browser therefore contacts its name server and says, "I need for you to convert a domain name to an IP address for me." For example, if you type "www.howstuffworks.com" into your browser, the browser needs to convert that URL into an IP address. The browser will hand "www.howstuffworks.com" to its default name server and ask it to convert it.
The name server may already know the IP address for www.howstuffworks.com. That would be the case if another request to resolve www.howstuffworks.com came in recently (name servers cache IP addresses to speed things up). In that case, the name server can return the IP address immediately. Let's assume, however, that the name server has to start from scratch.
A name server would start its search for an IP address by contacting one of the root name servers. The root servers know the IP address for all of the name servers that handle the top-level domains. Your name server would ask the root for www.howstuffworks.com, and the root would say (assuming no caching), "I don't know the IP address for www.howstuffworks.com, but here's the IP address for the COM name server." Obviously, these root servers are vital to this whole process, so:
• There are many of them scattered all over the planet.
• Every name server has a list of all of the known root servers. It contacts the first root server in the list, and if that doesn't work it contacts the next one in the list, and so on.
Here is a typical list of root servers held by a typical name server:
This file holds the information on root name servers
needed to initialize cache of Internet domain name
servers (e.g. reference this file in the
"cache ." configuration file of BIND domain : name servers).
This file is made available by InterNIC registration
services under anonymous FTP as
; file /domain/named.root
on server FTP.RS.INTERNIC.NET
-OR- under Gopher at RS.INTERNIC.NET
under menu InterNIC Registration Services (NSI)
submenu InterNIC Registration Archives
; file named.root
;
; last update: Aug 22, 1997
related version of root zone: 1997082200
formerly NS.INTERNIC.NET
;
. 3600000 IN NS A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4
;
; formerly NS1.ISI.EDU
;
. 3600000 NS B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET. 3600000 A 128.9.0.107
;
; formerly C.PSI.NET
;
. 3600000 NS C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12
;
if it knows the IP address for www.howstuffworks.com. It does, so it returns the IP address to your name server, which returns it to the browser, which can then contact the server for www.howstuffworks.com to get a Web page.
One of the keys to making this work is redundancy. There are multiple name servers at every level, so if one fails, there are others to handle the requests. There are, for example, three different machines running name servers for HOWSTUFFWORKS.COM requests. All three would have to fail for there to be a problem.
The other key is caching. Once a name server resolves a request, it caches all of the IP addresses it receives. Once it has made a request to a root server for any COM domain, it knows the IP address for a name server handling the COM domain, so it doesn't have to bug the root servers again for that information. Name servers can do this for every request, and this caching helps to keep things from bogging down.
Name servers do not cache forever, though. The caching has a component, called the Time To Live (TTL), that controls how long a server will cache a piece of information. When the server receives an IP address, it receives the TTL with it. The name server will cache the IP address for that period of time (ranging from minutes to days) and then discard it. The TTL allows changes in name servers to propagate. Not all name servers respect the TTL they receive, however. When HowStuffWorks moved its machines over to new servers, it took three weeks for the transition to propagate throughout the Web. We put a little tag that said "new server" in the upper left corner of the home page so people could tell whether they were seeing the new or the old server during the transition.
The browser therefore contacts its name server and says, "I need for you to convert a domain name to an IP address for me." For example, if you type "www.howstuffworks.com" into your browser, the browser needs to convert that URL into an IP address. The browser will hand "www.howstuffworks.com" to its default name server and ask it to convert it.
The name server may already know the IP address for www.howstuffworks.com. That would be the case if another request to resolve www.howstuffworks.com came in recently (name servers cache IP addresses to speed things up). In that case, the name server can return the IP address immediately. Let's assume, however, that the name server has to start from scratch.
A name server would start its search for an IP address by contacting one of the root name servers. The root servers know the IP address for all of the name servers that handle the top-level domains. Your name server would ask the root for www.howstuffworks.com, and the root would say (assuming no caching), "I don't know the IP address for www.howstuffworks.com, but here's the IP address for the COM name server." Obviously, these root servers are vital to this whole process, so:
• There are many of them scattered all over the planet.
• Every name server has a list of all of the known root servers. It contacts the first root server in the list, and if that doesn't work it contacts the next one in the list, and so on.
Here is a typical list of root servers held by a typical name server:
This file holds the information on root name servers
needed to initialize cache of Internet domain name
servers (e.g. reference this file in the
"cache .
This file is made available by InterNIC registration
services under anonymous FTP as
; file /domain/named.root
on server FTP.RS.INTERNIC.NET
-OR- under Gopher at RS.INTERNIC.NET
under menu InterNIC Registration Services (NSI)
submenu InterNIC Registration Archives
; file named.root
;
; last update: Aug 22, 1997
related version of root zone: 1997082200
formerly NS.INTERNIC.NET
;
. 3600000 IN NS A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4
;
; formerly NS1.ISI.EDU
;
. 3600000 NS B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET. 3600000 A 128.9.0.107
;
; formerly C.PSI.NET
;
. 3600000 NS C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12
;
if it knows the IP address for www.howstuffworks.com. It does, so it returns the IP address to your name server, which returns it to the browser, which can then contact the server for www.howstuffworks.com to get a Web page.
One of the keys to making this work is redundancy. There are multiple name servers at every level, so if one fails, there are others to handle the requests. There are, for example, three different machines running name servers for HOWSTUFFWORKS.COM requests. All three would have to fail for there to be a problem.
The other key is caching. Once a name server resolves a request, it caches all of the IP addresses it receives. Once it has made a request to a root server for any COM domain, it knows the IP address for a name server handling the COM domain, so it doesn't have to bug the root servers again for that information. Name servers can do this for every request, and this caching helps to keep things from bogging down.
Name servers do not cache forever, though. The caching has a component, called the Time To Live (TTL), that controls how long a server will cache a piece of information. When the server receives an IP address, it receives the TTL with it. The name server will cache the IP address for that period of time (ranging from minutes to days) and then discard it. The TTL allows changes in name servers to propagate. Not all name servers respect the TTL they receive, however. When HowStuffWorks moved its machines over to new servers, it took three weeks for the transition to propagate throughout the Web. We put a little tag that said "new server" in the upper left corner of the home page so people could tell whether they were seeing the new or the old server during the transition.
address that is assigned by the ISP when you dial in. That IP address is unique for your session and may be different the next time you dial in. In this way, an ISP only needs one IP address for each modem it supports, rather than for every customer.
If you are working on a Windows machine, you can view your current IP address with the command WINIPCFG.EXE (IPCONFIG.EXE for Windows 2000/XP). On a UNIX machine, type nslookup along with a machine name (such as "nslookup www.howstuffworks.com") to display the IP address of the machine (use the command hostname to learn the name of your machine).
For more information on IP addresses, see IANA.
As far as the Internet's machines are concerned, an IP address is all that you need to talk to a server. For example, you can type in your browser the URL http://216.183.103.150 and you will arrive at the machine that contains the Web server for HowStuffWorks. Domain names are strictly a human convenience.
If we had to remember the IP addresses of all of the Web sites we visit every day, we would all go nuts. Human beings just are not that good at remembering strings of numbers. We are good at remembering words, however, and that is where domain names come in. You probably have hundreds of domain names stored in your head. For example:
• www.howstuffworks.com - a typical name
• www.yahoo.com - the world's best-known name
• www.mit.edu - a popular EDU name
• encarta.msn.com - a Web server that does not start with www
• www.bbc.co.uk - a name using four parts rather than three
• ftp.microsoft.com - an FTP server rather than a Web server
The COM, EDU and UK portions of these domain names are called the top-level domain or first-level domain. There are several hundred top-level domain names, including COM, EDU, GOV, MIL, NET, ORG and INT, as well as unique two-letter combinations for every country.
Within every top-level domain there is a huge list of second-level domains. For example, in the COM first-level domain, you've got:
• howstuffworks
• yahoo
• msn
• microsoft
• plus millions of others...
Every name in the COM top-level domain must be unique, but there can be duplication across domains. For example, howstuffworks.com and howstuffworks.org are completely different machines.
In the case of bbc.co.uk, it is a third-level domain. Up to 127 levels are possible, although more than four is rare.
The left-most word, such as www or encarta, is the host name. It specifies the name of a specific machine (with a specific IP address) in a domain. A given domain can potentially contain millions of host names as long as they are all unique within that domain
If you are working on a Windows machine, you can view your current IP address with the command WINIPCFG.EXE (IPCONFIG.EXE for Windows 2000/XP). On a UNIX machine, type nslookup along with a machine name (such as "nslookup www.howstuffworks.com") to display the IP address of the machine (use the command hostname to learn the name of your machine).
For more information on IP addresses, see IANA.
As far as the Internet's machines are concerned, an IP address is all that you need to talk to a server. For example, you can type in your browser the URL http://216.183.103.150 and you will arrive at the machine that contains the Web server for HowStuffWorks. Domain names are strictly a human convenience.
If we had to remember the IP addresses of all of the Web sites we visit every day, we would all go nuts. Human beings just are not that good at remembering strings of numbers. We are good at remembering words, however, and that is where domain names come in. You probably have hundreds of domain names stored in your head. For example:
• www.howstuffworks.com - a typical name
• www.yahoo.com - the world's best-known name
• www.mit.edu - a popular EDU name
• encarta.msn.com - a Web server that does not start with www
• www.bbc.co.uk - a name using four parts rather than three
• ftp.microsoft.com - an FTP server rather than a Web server
The COM, EDU and UK portions of these domain names are called the top-level domain or first-level domain. There are several hundred top-level domain names, including COM, EDU, GOV, MIL, NET, ORG and INT, as well as unique two-letter combinations for every country.
Within every top-level domain there is a huge list of second-level domains. For example, in the COM first-level domain, you've got:
• howstuffworks
• yahoo
• msn
• microsoft
• plus millions of others...
Every name in the COM top-level domain must be unique, but there can be duplication across domains. For example, howstuffworks.com and howstuffworks.org are completely different machines.
In the case of bbc.co.uk, it is a third-level domain. Up to 127 levels are possible, although more than four is rare.
The left-most word, such as www or encarta, is the host name. It specifies the name of a specific machine (with a specific IP address) in a domain. A given domain can potentially contain millions of host names as long as they are all unique within that domain
Name servers do two things all day long:
• They accept requests from programs to convert domain names into IP addresses.
• They accept requests from other name servers to convert domain names into IP addresses.
When a request comes in, the name server can do one of four things with it:
• It can answer the request with an IP address because it already knows the IP address for the domain.
• It can contact another name server and try to find the IP address for the name requested. It may have to do this multiple times.
• It can say, "I don't know the IP address for the domain you requested, but here's the IP address for a name server that knows more than I do."
• It can return an error message because the requested domain name is invalid or does not exist.
When you type a URL into your browser, the browser's first step is to convert the domain name and host name into an IP address so that the browser can go request a Web page from the machine at that IP address (see How Web Servers Work for details on the whole process). To do this conversion, the browser has a conversation with a name server.
When you set up your machine on the Internet, you (or the software that you installed to connect to your ISP) had to tell your machine what name server it should use for converting domain names to IP addresses. On some systems, the DNS is dynamically fed to the machine when you connect to the ISP, and on other machines it is hard-wired. If you are working on a Windows 95/98/ME machine, you can view your current name server with the command WINIPCFG.EXE (IPCONFIG for Windows 2000/XP). On a UNIX machine, type nslookup along with your machine name. Any program on your machine that needs to talk to a name server to resolve a domain
; formerly TERP.UMD.EDU
;
. 3600000 NS D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90
;
; formerly NS.NASA.GOV
;
. 3600000 NS E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10
;
; formerly NS.ISC.ORG
;
. 3600000 NS F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241
;
; formerly NS.NIC.DDN.MIL
;
. 3600000 NS G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
;
. 3600000 NS H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53
;
; formerly NIC.NORDU.NET
;
. 3600000 NS I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17
;
; temporarily housed at NSI (InterNIC)
;
. 3600000 NS J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET. 3600000 A 198.41.0.10
;
; housed in LINX, operated by RIPE NCC
;
. 3600000 NS K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET. 3600000 A 193.0.14.129
;
; temporarily housed at ISI (IANA)
;
. 3600000 NS L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
;
; housed in Japan, operated by WIDE
;
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33
; End of File
The formatting is a little odd, but basically it shows you that the list contains the actual IP addresses of 13 different root servers.
The root server knows the IP addresses of the name servers handling the several hundred top-level domains. It returns to your name server the IP address for a name server for the COM domain. Your name server then sends a query to the COM name server asking it if it knows the IP address for www.howstuffworks.com. The name server for the COM domain knows the IP addresses for the name servers handling the HOWSTUFFWORKS.COM domain, so it returns those. Your name server then contacts the name server for HOWSTUFFWORKS.COM and asks
HowStuffWorks as well as the machine that hosted the HowStuffWorks Web pages. This type of machine is called a virtual Web hosting machine and is capable of hosting multiple domains simultaneously. Five-hundred or so different domains all shared the same processor.
As HowStuffWorks became more popular, it outgrew the virtual hosting machine and needed its own server. At that point, we started maintaining our own machines dedicated to HowStuffWorks, and began administering our own DNS. We have a primary server and a secondary:
• AUTH-NS1.HOWSTUFFWORKS.COM 209.116.69.78
• AUTH-NS2.HOWSTUFFWORKS.COM 209.116.69.79
Our primary DNS is auth-ns1.howstuffworks.com. Any changes we make to it propagate automatically to the secondary, which is also maintained by our ISP.
All of these machines run name server software called BIND. BIND knows about all of the machines in our domain through a text file on the main server that looks like this:
@ NS auth-ns1.howstuffworks.com.
@ NS auth-ns2.howstuffworks.com.
@ MX 10 mail
mail A 209.170.137.42
vip1 A 216.183.103.150
www CNAME vip1
Decoding this file from the top, you can see that:
• The first two lines point to the primary and secondary name servers.
• The next line is called the MX record. When you send e-mail to anyone at howstuffworks.com, the piece of software sending the e-mail contacts the name server to get the MX record so it knows where the SMTP server for HowStuffWorks is (see How E- mail Works for details). Many larger systems have multiple machines handling incoming e-mail, and therefore multiple MX records.
• The next line points to the machine that will handle a request to mail.howstuffworks.com.
• The next line points to the IP address that will handle a request to oak.howstuffworks.com.
• The next line points to the IP address that will handle a request to howstuffworks.com (no host name).
You can see from this file that there are several physical machines at separate IP addresses that make up the HowStuffWorks server infrastructure. There are aliases for hosts like mail and www. There can be aliases for anything. For example, there could be an entry in this file for scoobydoo.howstuffworks.com, and it could point to the physical machine called walnut. There could be an alias for yahoo.howstuffworks.com, and it could point to yahoo. There really is no limit to it. We could also create multiple name servers and segment our domain.
The Beauty of DNS
As you can see from this description, DNS is a rather amazing distributed database. It handles billions of requests for billions of names every day through a network of millions of name servers administered by millions of people. Every time you send an e-mail message or view a URL, you are making requests to multiple name servers scattered all over the globe. What's amazing is that the process is usually completely invisible and extremely reliable!
• They accept requests from programs to convert domain names into IP addresses.
• They accept requests from other name servers to convert domain names into IP addresses.
When a request comes in, the name server can do one of four things with it:
• It can answer the request with an IP address because it already knows the IP address for the domain.
• It can contact another name server and try to find the IP address for the name requested. It may have to do this multiple times.
• It can say, "I don't know the IP address for the domain you requested, but here's the IP address for a name server that knows more than I do."
• It can return an error message because the requested domain name is invalid or does not exist.
When you type a URL into your browser, the browser's first step is to convert the domain name and host name into an IP address so that the browser can go request a Web page from the machine at that IP address (see How Web Servers Work for details on the whole process). To do this conversion, the browser has a conversation with a name server.
When you set up your machine on the Internet, you (or the software that you installed to connect to your ISP) had to tell your machine what name server it should use for converting domain names to IP addresses. On some systems, the DNS is dynamically fed to the machine when you connect to the ISP, and on other machines it is hard-wired. If you are working on a Windows 95/98/ME machine, you can view your current name server with the command WINIPCFG.EXE (IPCONFIG for Windows 2000/XP). On a UNIX machine, type nslookup along with your machine name. Any program on your machine that needs to talk to a name server to resolve a domain
; formerly TERP.UMD.EDU
;
. 3600000 NS D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90
;
; formerly NS.NASA.GOV
;
. 3600000 NS E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10
;
; formerly NS.ISC.ORG
;
. 3600000 NS F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241
;
; formerly NS.NIC.DDN.MIL
;
. 3600000 NS G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
;
. 3600000 NS H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53
;
; formerly NIC.NORDU.NET
;
. 3600000 NS I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17
;
; temporarily housed at NSI (InterNIC)
;
. 3600000 NS J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET. 3600000 A 198.41.0.10
;
; housed in LINX, operated by RIPE NCC
;
. 3600000 NS K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET. 3600000 A 193.0.14.129
;
; temporarily housed at ISI (IANA)
;
. 3600000 NS L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
;
; housed in Japan, operated by WIDE
;
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33
; End of File
The formatting is a little odd, but basically it shows you that the list contains the actual IP addresses of 13 different root servers.
The root server knows the IP addresses of the name servers handling the several hundred top-level domains. It returns to your name server the IP address for a name server for the COM domain. Your name server then sends a query to the COM name server asking it if it knows the IP address for www.howstuffworks.com. The name server for the COM domain knows the IP addresses for the name servers handling the HOWSTUFFWORKS.COM domain, so it returns those. Your name server then contacts the name server for HOWSTUFFWORKS.COM and asks
HowStuffWorks as well as the machine that hosted the HowStuffWorks Web pages. This type of machine is called a virtual Web hosting machine and is capable of hosting multiple domains simultaneously. Five-hundred or so different domains all shared the same processor.
As HowStuffWorks became more popular, it outgrew the virtual hosting machine and needed its own server. At that point, we started maintaining our own machines dedicated to HowStuffWorks, and began administering our own DNS. We have a primary server and a secondary:
• AUTH-NS1.HOWSTUFFWORKS.COM 209.116.69.78
• AUTH-NS2.HOWSTUFFWORKS.COM 209.116.69.79
Our primary DNS is auth-ns1.howstuffworks.com. Any changes we make to it propagate automatically to the secondary, which is also maintained by our ISP.
All of these machines run name server software called BIND. BIND knows about all of the machines in our domain through a text file on the main server that looks like this:
@ NS auth-ns1.howstuffworks.com.
@ NS auth-ns2.howstuffworks.com.
@ MX 10 mail
mail A 209.170.137.42
vip1 A 216.183.103.150
www CNAME vip1
Decoding this file from the top, you can see that:
• The first two lines point to the primary and secondary name servers.
• The next line is called the MX record. When you send e-mail to anyone at howstuffworks.com, the piece of software sending the e-mail contacts the name server to get the MX record so it knows where the SMTP server for HowStuffWorks is (see How E- mail Works for details). Many larger systems have multiple machines handling incoming e-mail, and therefore multiple MX records.
• The next line points to the machine that will handle a request to mail.howstuffworks.com.
• The next line points to the IP address that will handle a request to oak.howstuffworks.com.
• The next line points to the IP address that will handle a request to howstuffworks.com (no host name).
You can see from this file that there are several physical machines at separate IP addresses that make up the HowStuffWorks server infrastructure. There are aliases for hosts like mail and www. There can be aliases for anything. For example, there could be an entry in this file for scoobydoo.howstuffworks.com, and it could point to the physical machine called walnut. There could be an alias for yahoo.howstuffworks.com, and it could point to yahoo. There really is no limit to it. We could also create multiple name servers and segment our domain.
The Beauty of DNS
As you can see from this description, DNS is a rather amazing distributed database. It handles billions of requests for billions of names every day through a network of millions of name servers administered by millions of people. Every time you send an e-mail message or view a URL, you are making requests to multiple name servers scattered all over the globe. What's amazing is that the process is usually completely invisible and extremely reliable!
If you spend any time on the Internet sending e-mail or browsing the Web, then you use domain name servers without even realizing it. Domain name servers, or DNS, are an incredibly important but completely hidden part of the Internet, and they are fascinating! The DNS system forms one of the largest and most active distributed databases on the planet. Without DNS, the Internet would shut down very quickly.
In this edition of HowStuffWorks, we will take a look at the DNS system so you can understand how it works and appreciate its amazing capabilities.
The Basics
When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL "http://www.howstuffworks.com" contains the domain name howstuffworks.com. So does the e-mail address "iknow@howstuffworks.com."
Human- readable names like "howstuffworks.com" are easy for people to remember, but they don't do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "www.howstuffworks.com" has the IP address 216.183.103.150. Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address. During a day of browsing and e-mailing, you might access the domain name servers hundreds of times!
Domain name servers translate domain names to IP addresses. That sounds like a simple task, and it would be -- except for five things:
• There are billions of IP addresses currently in use, and most machines have a human-readable name as well.
• There are many billions of DNS requests made every day. A single person can easily make a hundred or more DNS requests a day, and there are hundreds of millions of people and machines using the Internet daily.
• Domain names and IP addresses change daily.
• New domain names get created daily.
• Millions of people do the work to change and add domain names and IP addresses every day.
The DNS system is a database, and no other database on the planet gets this many requests. No other database on the planet has millions of people changing it every day, either. That is what makes the DNS system so unique!
IP Addresses
To keep all of the machines on the Internet straight, each machine is assigned a unique address called an IP address. IP stands for Internet protocol, and these addresses are 32-bit numbers normally expressed as four "octets" in a "dotted decimal number." A typical IP address looks like this:
216.183.103.150
The four numbers in an IP address are called octets because they can have values between 0 and 255 (28 possibilities per octet).
Every machine on the Internet has its own IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP
Because all of the names in a given domain need to be unique, there has to be a single entity that controls the list and makes sure no duplicates arise. For example, the COM domain cannot contain any duplicate names, and a company called Network Solutions is in charge of maintaining this list. When you register a domain name, it goes through one of several dozen registrars who work with Network Solutions to add names to the list. Network Solutions, in turn, keeps a central database known as the whois database that contains information about the owner and name servers for each domain. If you go to the whois form, you can find information about any domain currently in existence.
While it is important to have a central authority keeping track of the database of names in the COM (and other) top-level domain, you would not want to centralize the database of all of the information in the COM domain. For example, Microsoft has hundreds of thousands of IP addresses and host names. Microsoft wants to maintain its own domain name server for the microsoft.com domain. Similarly, Great Britain probably wants to administrate the uk top-level domain, and Australia probably wants to administrate the au domain, and so on. For this reason, the DNS system is a distributed database. Microsoft is completely responsible for dealing with the name server for microsoft.com -- it maintains the machines that implement its part of the DNS system, and Microsoft can change the database for its domain whenever it wants to because it owns its domain name servers.
Every domain has a domain name server somewhere that handles its requests, and there is a person maintaining the records in that DNS. This is one of the most amazing parts of the DNS system -- it is completely distributed throughout the world on millions of machines administered by millions of people, yet it behaves like a single, integrated database!
In this edition of HowStuffWorks, we will take a look at the DNS system so you can understand how it works and appreciate its amazing capabilities.
The Basics
When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL "http://www.howstuffworks.com" contains the domain name howstuffworks.com. So does the e-mail address "iknow@howstuffworks.com."
Human- readable names like "howstuffworks.com" are easy for people to remember, but they don't do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "www.howstuffworks.com" has the IP address 216.183.103.150. Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address. During a day of browsing and e-mailing, you might access the domain name servers hundreds of times!
Domain name servers translate domain names to IP addresses. That sounds like a simple task, and it would be -- except for five things:
• There are billions of IP addresses currently in use, and most machines have a human-readable name as well.
• There are many billions of DNS requests made every day. A single person can easily make a hundred or more DNS requests a day, and there are hundreds of millions of people and machines using the Internet daily.
• Domain names and IP addresses change daily.
• New domain names get created daily.
• Millions of people do the work to change and add domain names and IP addresses every day.
The DNS system is a database, and no other database on the planet gets this many requests. No other database on the planet has millions of people changing it every day, either. That is what makes the DNS system so unique!
IP Addresses
To keep all of the machines on the Internet straight, each machine is assigned a unique address called an IP address. IP stands for Internet protocol, and these addresses are 32-bit numbers normally expressed as four "octets" in a "dotted decimal number." A typical IP address looks like this:
216.183.103.150
The four numbers in an IP address are called octets because they can have values between 0 and 255 (28 possibilities per octet).
Every machine on the Internet has its own IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP
Because all of the names in a given domain need to be unique, there has to be a single entity that controls the list and makes sure no duplicates arise. For example, the COM domain cannot contain any duplicate names, and a company called Network Solutions is in charge of maintaining this list. When you register a domain name, it goes through one of several dozen registrars who work with Network Solutions to add names to the list. Network Solutions, in turn, keeps a central database known as the whois database that contains information about the owner and name servers for each domain. If you go to the whois form, you can find information about any domain currently in existence.
While it is important to have a central authority keeping track of the database of names in the COM (and other) top-level domain, you would not want to centralize the database of all of the information in the COM domain. For example, Microsoft has hundreds of thousands of IP addresses and host names. Microsoft wants to maintain its own domain name server for the microsoft.com domain. Similarly, Great Britain probably wants to administrate the uk top-level domain, and Australia probably wants to administrate the au domain, and so on. For this reason, the DNS system is a distributed database. Microsoft is completely responsible for dealing with the name server for microsoft.com -- it maintains the machines that implement its part of the DNS system, and Microsoft can change the database for its domain whenever it wants to because it owns its domain name servers.
Every domain has a domain name server somewhere that handles its requests, and there is a person maintaining the records in that DNS. This is one of the most amazing parts of the DNS system -- it is completely distributed throughout the world on millions of machines administered by millions of people, yet it behaves like a single, integrated database!
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