complicated than the simple example displayed earlier. Here is an example. In the example above, someone is viewing a web page called “creating-links.asp.” As mentioned earlier, this web page is a file, in this case an ASP file rather than an HTML file. This file resides within a directory folder called html. This folder exists within the domain name, scriptingmaster.com. DNS DNS stands for Domain Name System. DNS is an essential protocol for the Internet. Without it, surfing the Internet would be far more difficult than it actually is. The reason is that computers deal with IP addresses and people deal with domain names. Computers like numbers, numbers like 22.214.171.124. This, in fact, is one of the IP addresses for Google.com—one of the addresses because the Google website is made up of many, many servers. Microsoft.com is 126.96.36.199. When you type into your web browser, that domain name means nothing to your computer. It wants an IP address. Thankfully, people don’t have to remember the IP address of every website they frequent. When a user types into his or her computer, that computer looks to see if it knows what the IP address of is. If it doesn’t, it is programmed to contact a DNS server on the Internet. Usually this is the DNS server hosted by the ISP. A DNS server keeps a list that matches websites to IP addresses. When a client computer asks a DNS server to resolve a domain name to an IP address, it is called a DNS query. If the DNS server knows the IP address of the given domain name, it will inform the client computer of the IP address. If it doesn’t, the DNS server will proceed to ask other DNS servers throughout the Internet about that domain name. This is called a recursive query. Once the DNS server receives the answer from another server, it caches the answer so that it can answer future queries. The client computer caches the answer as well for a short period of time in case the user decides to visit the URL again. You can read about the DNS Query procedure in more detail at -
us/library/cc775637(v=ws.10).aspx. HTTPS When a user visits Amazon.com and searches for a product to buy, the user visits and surfs the website using HTTP. As soon as the user wants to begin the purchase process, however, the URL changes from HTTP to HTTPS. The “S” stands for secure. HTTPS means that the connection to the website is now encrypted. This means that if someone were to tap into the connection, the user’s identity information and credit card number typed into a form cannot be captured or seen. HTTPS encrypts traffic by using a certificate. A Certificate is a document that your website shows a browser to proclaim its identity. It “certifies” that the website is who it says it is. It includes web information like the organization’s domain name (e.g., “amazon.com”) and also identification information like the organization’s name, address, phone number, and so forth. Some certificates provide more information than others, but this is the general idea. A certificate is issued by a CA. CA stands for
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