{"id":868,"date":"2026-03-06T09:54:14","date_gmt":"2026-03-06T09:54:14","guid":{"rendered":"https:\/\/networkingnotebook.com\/?p=868"},"modified":"2026-03-07T08:56:21","modified_gmt":"2026-03-07T08:56:21","slug":"dns","status":"publish","type":"post","link":"https:\/\/networkingnotebook.com\/?p=868","title":{"rendered":"DNS"},"content":{"rendered":"\n

Today I am going to talk about DNS which stands for Domain Name System. DNS is a system that allows for users to access web servers or websites via human-readable domain names instead of an IP number. An IP address consists of 32 bits, and is formatted in dotted decimal format to make it more readable. Even though it is more readable to humans, it is harder to remember multiple IP addresses to multiple websites simultaneously. It’s kind of like phone numbers and having contacts. When a contact is added on a phone, instead of typing someone’s number, I can just click their name and call them. DNS does that except for the Internet, essentially acting as the phonebook of the Internet. Because of DNS, I am able to type in www.google.com instead of 8.8.8.8. <\/p>\n\n\n\n

DNS Resolver- <\/strong>DNS is just a system, and that system has multiple things in place to orchestrate how it works. The first thing that allows DNS to operate on the Internet is a DNS resolver. The DNS resolver is a server or service that is responsible for handling DNS queries on behalf of a client. This is a server or service that will do the \u201cheavy lifting\u201d of finding out the IP address by contacting multiple servers and once it gets that IP address it will then return it to the client. A DNS resolver goes through a series of query steps in order to get the final IP address (not including checking cache). The DNS resolver first queries a root server. The root server provides referrals to the appropriate Top Level Domain Servers. When queried by the DNS resolver it will then refer the DNS resolver to a Top Level Domain Server. This server is responsible for referring the DNS resolver to the appropriate authoritative server. Once the top level domain server is queried, it will then refer the resolver to a list of authoritative servers. These are servers that are responsible for holding the actual DNS records for the domain. This is the final server that will provide the DNS resolver the IP address it is looking for. Once the DNS resolver receives that IP address, it will then deliver that IP to the client. <\/p>\n\n\n\n

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DNS Cache- <\/strong>Once that is done, the DNS resolver will then put that DNS query result inside of its DNS cache. A DNS cache is a temporary storage where recently queried name resolution results are stored. The DNS cache is stored by the web browser, the OS (Operating System), and the DNS resolver so when the domain IP address is requested again it can be resolved at a much quicker rate without contacting any DNS servers. Because the DNS cache can resolve DNS queries, they can not only reduce latency but also reduce unnecessary network traffic for repeat requests. In order to avoid outdated and stale DNS query results, the entries inside of a DNS cache are stored only for a certain amount of time defined by the TTL (Time to Live.) Once the TTL has expired for an entry, the DNS resolution has to be done all over again. <\/p>\n\n\n\n

Hosts File-<\/strong> On top of a DNS cache, most operating systems have a plain text file stored in its system called a \u201chosts file.\u201d This file functions just like a DNS cache except it does not have a TTL. It holds human readable domain names that are mapped to an IP address that is typically checked before a DNS query is sent to a DNS resolver. So if I type in google.com<\/a> and there is an entry on the hosts file, the DNS query will not be sent to the DNS resolver.<\/p>\n","protected":false},"excerpt":{"rendered":"

Today I am going to talk about DNS which stands for Domain Name System. DNS is a system that allows for users to access web servers or websites via human-readable domain names instead of an IP number. An IP address consists of 32 bits, and is formatted in dotted decimal format to make it more…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-868","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/posts\/868","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=868"}],"version-history":[{"count":3,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/posts\/868\/revisions"}],"predecessor-version":[{"id":873,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=\/wp\/v2\/posts\/868\/revisions\/873"}],"wp:attachment":[{"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=868"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=868"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/networkingnotebook.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=868"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}