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Okay, ready to get started on Lesson 7? Here we go…
There and Back Again: A Packet’s Tale – How does the Internet work? –
Okay, it’s a little more complicated than that, but even just the basics are good to know. If you want a little more detail when it comes to IP addresses check out this article for “extra credit.”
So why do you need to know all this?
When it works, which it does most of the time, you really don’t need to know how it works. Just enjoy the magic that is the internet. But when it doesn’t work, well that’s a different story and that’s where knowing how the internet is put together can help you figure out what might be going wrong.
Trouble-shooting Internet Problems: or what do you do when you click on a link and things go awry.
When trying to trouble-shoot any problem that involves a complex process, the key is in figuring out where things start to fall apart. Trouble-shooting online is no different – you need to figure out where the roadblock lies (after all, this is the information highway) and see if there is a way to remove it or work around it.
Let’s go through some common errors you might run into. In some of these examples there will be a link you can try so you can see what that particular error might look like. To make life easier, try right clicking the link and opening it in a new tab. For even more fun, try the links in different browsers; the error messages are often similar, but sometimes they can vary quite a bit.
Server not found or similar errors (http://www.gooble.com/ for information about “Dinner Kits” for fast meals)
First, make sure you can get to other sites. The easiest thing is to try going to a site you know should be working, like http://google.com. If you can get there then the problem isn’t your connection to the internet, but something else.
If you can get to Google.com, you can also try searching for the site you were trying to get to originally. This will ensure you’ve got the right URL. You can search for the URL itself or try searching for the name of the site or words that describe the site.
If the URL checks out, see if the site itself is having problems by using a service like Down for Everyone Or Just Me. These sites will attempt to navigate to the page in question from multiple locations to help determine if it’s your connection that isn’t working properly or the if site you were trying to visit is itself having problems.
What if the site is fine, but the exact page you want isn’t?
Another common error you will come across is the 404: Page Not Found Error. Try going to http://mysapl.org/11.5cosas.aspx In this case, the server is real (mysapl.org) but the actual web page you’re looking for (11.5cosas.aspx) has either been incorrectly linked or no longer exists on the server.
The easiest work around for this type of problem is to try going to the main page of the web site and then navigating your way to the page you want; or if the site offers a search function, you can search the site for the correct page.
To find the main page it helps to understand how a URL is constructed. Each part of a URL helps inform the computers that route internet traffic just where and what you are looking for. Here’s a URL that points to the location page for Collins Garden: http://www.mysapl.org/location.aspx?id=col
The first part of the URL specifies the type of protocol that is used in accessing the resource you’re looking for, so in this case it is – HTTP:// (which stands for hyper-text transfer protocol). What that really means is that you’re asking for the internet to take you to a web page. You’ll often see a variation on this, HTTPS://. The only different here is that the connection is “secure” – your requests and the web server’s responses are all being encrypted to protect them from being read by other people or computers.
The next part is what appears between the “://” and the next “/”. In the example above, that would be “www.mysapl.org.” This is the part of the URL that the internet routers use to find the correct web server, which is in turn made up of several parts itself. In most cases (in the US at least) the parts on either side of the last period (mysapl.org) define the top level “domain” which is the part that gets translated into an IP address by the Domain Name System (DNS) as shown in the video. You can actually bypass DNS servers if you know the IP address of a web site. You can actually get to mysapl.org this way: http://126.96.36.199/ – but who really wants to remember a bunch of numbers. The part that comes before the top level domain (in our example, the “www”) is sometimes called a sub-domain. It is used for a variety purposes, but primarily it serves to redirect or further refine the location where the request will end up.
EXTRA KNOWLEDGE (may be skipped by the faint of heart). Here’s a snarky little video that actually does a pretty good job describing how DNS works: https://www.youtube.com/watch?v=72snZctFFtA
The last part of a URL is everything after the domain name. For our example, that would be “location.aspx?id=col” Again, there are couple of parts here. Everything up to the “?” is the name of the page you’re requesting from the server. In our example, we are asking for the page named location.aspx. The stuff on the other side of the “?” are further instructions to the server, and determine what ends up on the page the server is returning. Location.aspx is what is often referred to as a dynamic page – it’s a template that gets filled in by the server based on the information you give it. In this case we’re giving it id=col which tells the server to fill in the page with the information for Collins Garden. Information passed this way is done in what are called key pairs. The “id” part is the key and the value for that key is “col.” If you change the “col” to “cod” (and hit return) you’ll now see the information for Cody instead. You can have multiple key pairs in a URL, and those pairs will always be separated by the “&” symbol (for example http://www.intranet.sat.lib.tx.us/announce/news/staffnotes.asp?linkid=16¬etype=1 has two key pairs: linkid=16 and notetype=1).
If you’ve ever clicked on a link in an email and it didn’t work, it’s often because the link has been “broken” (to the computer it appears as two or more lines instead of one single line), and that often means that the key pairs needed are missing or incomplete. While servers try to account for these errors, they are not always successful. Our example above does try to account for the more common errors: try http://www.mysapl.org/location.aspx and pay very close attention to the name of the page in the URL.
To return our original problem, that annoying 404 Page Not Found error, we can try and work around the problem by removing everything after the first “slash.” Instead of using the whole URL, we can just type http://mysapl.org and then try and find our way from there. Bad links happen all the time no matter how hard web masters try and keep them up to date. The internet is in constant flux – so don’t be surprised if what worked a month ago doesn’t work today.
Pages not loading properly or behaving oddly.
This is a good time to talk about web pages and how they work. At the most basic level web pages are comprised of two elements: structure and style. Structure defines how the page is displayed: what goes in the header, body and footer of the page (and a whole bunch of other pieces as well). Style defines how it looks: how big is the font, what is the background color, how bold is bold, does it flash annoyingly, etc. Most of this stuff is pretty basic and doesn’t often cause many problems (and what problems do arise are often the result of non-standard browser features).
There is a third element of web design, however, one that really opens up what you can do online, but which can also cause headaches. That third element is Behavior. The simplest level of behavior has been around since the beginning of the web: the links themselves and web forms. Both cause something to happen in the browser. Modern web sites can now offer a whole lot more – audio, video, response design; just to name a few. When it comes to problem solving, it’s easier to lump Behavior into two categories: Server side behavior and Browser side behavior.
Server side behavior is anything that happens before the page arrives at your browser. As mentioned above, the parts of the URL following the “?” can trigger server side behavior. Other common examples are a web site including date and time information or your log-in name, or other important information. The thing to remember is that the content is added to the page before it’s even sent to your browser. There isn’t much you can do about server side behavior if it misbehaves.
Trouble-shooting browser side behavior is kind of tricky, but there are several things you can try that might help determine where the problem lies:
- Clear your browser cache
- Try a different browser
- Try compatibility mode if the browser supports it (I’m looking at you Internet Explorer)
If you are not sure how to clear the cache in your browser, remember: the web is your friend – just do a web search. Also remember, when doing a search like that, the more information you provide the better the results. Do searches like, “how do I clear the cache in Internet Explorer 11,” rather than just just “clear cache.”
Trying each of these things will at least give you a better idea of the problem. If none of them help, then the problem probably lies with the page itself and there is little you can to fix that. Bad pages happen (all too often) and it’s not always entirely the web designers fault either. The web is a dynamic, ever changing, ever evolving, conglomeration of millions of different networks. When you really think about everything that goes on in the background in order for you to read this blog post, it’s pretty amazing how well it works.
Optional Challenge: Please name this blog entry: Lesson 7 Challenge
How many times have you come across a 404 page? Have any favorites? Visit Creative Bloq to see some creative 404 designs.
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