{"id":1345,"date":"2013-06-27T06:08:37","date_gmt":"2013-06-27T06:08:37","guid":{"rendered":"http:\/\/microsoftgeek.com\/?p=1345"},"modified":"2013-06-27T06:08:37","modified_gmt":"2013-06-27T06:08:37","slug":"what-is-dns","status":"publish","type":"post","link":"https:\/\/microsoftgeek.com\/?p=1345","title":{"rendered":"What is DNS?"},"content":{"rendered":"
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Did you know you could be connected to facebook.com \u2013 and see facebook.com in your web browser\u2019s address bar \u2013 while not actually being connected to Facebook\u2019s real website? To understand why, you\u2019ll need to know a bit about DNS.<\/p>\n

DNS underpins the world wide web we use every day. It works transparently in the background, converting human-readable website names into computer-readable numerical IP addresses.<\/p>\n

Image Credit: Jemimus on Flickr<\/a><\/small><\/p>\n

Domain Names and IP Addresses<\/h3>\n

DNS stands for \u201cdomain name system.\u201d Domain names are the human-readable website addresses we use every day. For example, Google\u2019s domain name is google.com. If you want to visit Google, you just need to enter google.com into your web browser\u2019s address bar.<\/p>\n

However, your computer doesn\u2019t understand where \u201cgoogle.com\u201d is. Behind the scenes, the Internet and other networks use numerical IP addresses (\u201cInternet protocol\u201d addresses). Google.com is located at the IP address 173.194.39.78 on the Internet. If you typed this number into your web browser\u2019s address bar, you\u2019d also end up at Google\u2019s website.<\/p>\n

We use google.com instead of 173.194.39.78 because addresses like google.com are more meaningful and easier for us to remember. DNS is often explained as being like a phone book \u2013 like a phone book, DNS matches human-readable names to numbers that machines can more easily understand.<\/p>\n

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DNS Servers<\/h3>\n

Domain name system servers match domain names like google.com to their associated IP addresses \u2014 173.194.39.78 in the case of google.com. When you type google.com into your web browser\u2019s address bar, your computer contacts your current DNS server and asks what IP address is associated with google.com. Your computer then connects to the IP address and displays \u201cgoogle.com\u201d in your web browser \u2013 the connection to 173.194.39.78 happens behind the scenes.<\/p>\n

The DNS servers you use are likely provided by your Internet service provider (\u201cISP\u201d). If you\u2019re behind a router, your computer is likely using your router as your DNS server, but the router is likely forwarding requests to your Internet service provider\u2019s DNS servers.<\/p>\n

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Computers cache DNS responses, so the DNS request doesn\u2019t happen each time you connect to google.com. Once your computer has determined the IP address associated with a domain name, it will remember that for a period of time \u2013 this improves connection speed by skipping the DNS request phase. Your computer just needs to connect to Google, not its DNS server and then Google.<\/p>\n

Security Concerns<\/h3>\n

Some viruses and other malware programs change your default DNS server to a DNS server run by a malicious organization or scammer. This malicious DNS server can point popular websites to different IP addresses, which could be run by scammers.<\/p>\n

For example, when you connect to facebook.com while using your Internet service provider\u2019s legitimate DNS server, the DNS server will respond with the actual IP address of Facebook\u2019s servers.<\/p>\n

However, if your computer or network is pointed at a malicious DNS server set up by a scammer, the malicious DNS server could respond with a different IP address entirely. In this way, it\u2019s possible that you could see \u201cfacebook.com\u201d in your web browser\u2019s address bar, but you may not actually be at the real facebook.com \u2013 behind the scenes, the malicious DNS server has pointed you to a different IP address.<\/p>\n

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To avoid this problem, ensure you\u2019re running antivirus software. You should also watch for certificate error messages on encrypted (HTTPS) websites. For example, if you try to connect to your bank\u2019s website and see an \u201cinvalid certificate\u201d message, this could be a sign that you\u2019re using a malicious DNS server that\u2019s pointing you to a fake website, which is only pretending to be your bank.<\/p>\n

Malware can also use your computer\u2019s hosts file to override your DNS server and point certain domain names (websites) at other IP addresses.<\/p>\n

Why You Might Want To Use Third-Party DNS Servers<\/h3>\n

As we\u2019ve established above, you\u2019re probably using your Internet service provider\u2019s default DNS servers. However, you don\u2019t have to \u2013 you can use DNS servers run by a third party instead of your default DNS servers. Two of the most popular third-party DNS servers are OpenDNS<\/a> and Google Public DNS<\/a>.<\/p>\n

In some cases, these DNS servers may provide you with faster DNS resolves, speeding up your connection the first time you connect to a domain name. However, the actual speed differences you see will vary depending on how far you are from the third-party DNS servers and how fast your ISP\u2019s DNS servers are. If your ISP\u2019s DNS servers are fast and you\u2019re located a long way from OpenDNS or Google DNS\u2019s servers, you may see slower DNS resolves with a third-party DNS server.<\/p>\n

OpenDNS also provides optional website filtering. For example, if you enable the filtering, accessing a pornographic website from your network could result in a \u201cBlocked\u201d page appearing instead of the pornographic website. Behind the scenes, OpenDNS has returned the IP address of a website with a \u201cBlocked\u201d messsage instead of the IP address of the pornographic website \u2013 this takes advantage of the way DNS works to block websites.<\/p>\n

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Did you know you could be connected to facebook.com \u2013 and see facebook.com in your web browser\u2019s address bar \u2013 while not actually being connected to Facebook\u2019s real website? To understand why, you\u2019ll need to know a bit about DNS. DNS underpins the world wide web we use every day. It works transparently in the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[45],"tags":[],"class_list":["post-1345","post","type-post","status-publish","format-standard","hentry","category-domain-name-system-dns"],"_links":{"self":[{"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/posts\/1345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1345"}],"version-history":[{"count":2,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/posts\/1345\/revisions"}],"predecessor-version":[{"id":1347,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=\/wp\/v2\/posts\/1345\/revisions\/1347"}],"wp:attachment":[{"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microsoftgeek.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}