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Before we get to AWS, the first part is to get an overview of the internet, and how systems work on the internet
DNS (Domain Name System) is a hierarchical and decentralized naming system for Internet connected resources. DNS maintains a list of domain names along with the resources, such as IP addresses, that are associated with them.
The most prominent function of DNS is the translation of human-friendly domain names (such as
) to a numeric IP address (such as 151.106.5.172); this process of mapping a domain name to the appropriate IP address is known as a DNS lookup. By contrast, a reverse DNS lookup (rDNS) is used to determine the domain name associated with an IP address.
. => 93.184.216.119
Elements of the name:
Domain names are a key part of the Internet infrastructure. They provide a human-readable address for any web server available on the Internet.
Any Internet-connected computer can be reached through a public IP address, either an IPv4 address (e.g. 173.194.121.32) or an IPv6 address (e.g., 2027:0da8:8b73:0000:0000:8a2e:0370:1337).
Computers can handle such addresses easily, but people have a hard time finding out who's running the server or what service the website offers. IP addresses are hard to remember and might change over time.
To solve all those problems we use human-readable addresses called domain names.
A domain name has a simple structure made of several parts (it might be one part only, two, three...), separated by dots and read from right to left:
Each of those parts provides specific information about the whole domain name.
TLDs tell users the general purpose of the service behind the domain name. The most generic TLDs (.com, .org, .net) don't require web services to meet any particular criteria, but some TLDs enforce stricter policies so it is clearer what their purpose is. For example:
Local TLDs such as .us, .fr, or .se can require the service to be provided in a given language or hosted in a certain country — they are supposed to indicate a resource in a particular language or country. TLDs containing .gov are only allowed to be used by government departments. The .edu TLD is only for use by educational and academic institutions. TLDs can contain special as well as latin characters. A TLD's maximum length is 63 characters, although most are around 2–3.
The full list of TLDs is maintained by ICANN.
Who owns a domain name? You cannot “buy a domain name”. This is so that unused domain names eventually become available to use again by someone else. If every domain name was bought, the web would quickly fill up with unused domain names that were locked and couldn't be used by anyone.
Instead, you pay for the right to use a domain name for one or more years. You can renew your right, and your renewal has priority over other people's applications. But you never own the domain name.
Companies called registrars use domain name registries to keep track of technical and administrative information connecting you to your domain name.
When launching a website, you may spend nothing, or your costs may go through the roof. In this article we discuss how much everything costs, and how you get what you pay (or don't pay).
A: ipv4 address \[www.example.com:80\]
AAAA: ipv6 address \[www.example.com:80\]
MX: mail exchanger \[
\]
CNAME: alias resolves to another domain name \[irc.example.com:6669\]
TXT: text \[darknet.example.com:1337\]
NS: name server \[
\]
ANY: any record type that exists for the subject of the query
HINFO: host information. Information about the CPU type and operating system of subject of the query
WKS: well-known services or applications available on this host
PTR: pointer record. Returns a host name for an IP address
SOA: start of Authority record
SRV: service record is a specification of data in the Domain Name System defining the location, i.e. the hostname and port number, of servers for specified services
Checks information about ownership of a domain name
$ whois [domain] - querying databases that store the registered users or assignees, such as a domain name, an IP addresses
Example: $ whois
Domain Name:
Registry Domain ID: 2370838678_DOMAIN_COM-VRSN Registrar WHOIS Server: