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Route 53

Route 53 has the ability to manage the DNS records for domain names. You can register new domain names directly in Route 53. You can also transfer DNS records for existing domain names managed by other domain registrars. This enables you to manage all of your domain names within a single location.

Route 53 supports up to 50 domain names by default, but this limit can be raised if requested.

A naked domain is a DNS name that can't be a canonical name record (CNAME). An example is hello.com, without the www subdomain

Type of DNS records

  • A record : It maps a name to one or more IPv4 addresses when the IP is known and stable. 
    192.0.2.1
  • AAAA record : It maps a name to one or more IPv6 addresses
2001:0db8:85a3:0:0:8a2e:0370:7334

<Value>2001:0db8:85a3:0:0:8a2e:0370:7334</Value>
  • CNAME record : It maps a hostname to another hostname. It should only be used when there are no other records on that name.

Example

A CNAME record maps DNS queries for the name of the current record, such as acme.example.com, to another domain (example.com or example.net) or subdomain (acme.example.com or zenith.example.org).

  • ALIAS record : It maps a name to another name but can coexist with other records on that name.
  • MX: An MX record specifies the names of your mail servers and, if you have two or more mail servers, the priority order. Each value for an MX record contains two values, priority and domain name.
10 mail.example.com
  • SOA: A start of authority (SOA) record provides information about a domain and the corresponding Amazon Route 53 hosted zone. For information about the fields in an SOA record.
ns-2048.awsdns-64.net hostmaster.awsdns.com 1 1 1 1 60Ăź
  • PTR: Getting reverse DNS going is done by finding the PTR records in use by a DNS server. 

  • TXT: Used to privide info in a text format to the systems outside of your domain. A TXT record contains one or more strings that are enclosed in double quotation marks ("). When you use the simple routing policy, include all values for a domain (example.com) or subdomain (www.example.com) in the same TXT record.

    A single string can include up to 255 characters, including the following:

    • a-z
    • A-Z
    • 0-9
    • Space
      • (hyphen)
    • ! " # $ % & ' ( ) * + , - / : ; < = > ? @ [ ] ^ _ ` { | } ~ .

    If you need to enter a value longer than 255 characters, break the value into strings of 255 characters or fewer, and enclose each string in double quotation marks ("). In the console, list all the strings on the same line:

    "String 1" "String 2" "String 3"
  • NS (NameServer): This record indicates which DNS server is authoritative for that domain (which server contains the actual DNS records). A domain will often have multiple NS records which can indicate primary and backup name servers for that domain.
  • Alias Record: This is unique to AWS using which maps requests to AWS resources.

Some rules:

  • The A, CNAME, and ALIAS records cause a name to resolve to an IP. Conversely, the URL record redirects the name to a destination. The URL record is a simple and effective way to apply a redirect for one name to another name, for example redirecting www.example.com to example.com.
  • The A name must resolve to an IP. The CNAME and ALIAS records must point to a name.

Concepts

Alias record

A type of record that you can create with Amazon Route 53 to route traffic to AWS resources such as Amazon CloudFront distributions and Amazon S3 buckets

Auth Name Server 🎰

A name server that has definitive information about one part of the Domain Name System (DNS) and that responds to requests from a DNS resolver by returning the applicable information.

Example

An authoritative name server for the .com top-level domain (TLD) knows the names of the name servers for every registered .com domain. When a .com authoritative name server receives a request from a DNS resolver for example.com, it responds with the names of the name servers for the DNS service for the example.com domain.

Route 53 name servers are the authoritative name servers for every domain that uses Route 53 as the DNS service. The name servers know how you want to route traffic for your domain and subdomains based on the records that you created in the hosted zone for the domain. (Route 53 name servers store the hosted zones for the domains that use Route 53 as the DNS service.)

If a Route 53 name server receives a request for www.example.com, it finds that record and returns the IP address, such as 192.0.2.33, that is specified in the record.

CIDR block 🎛️

A CIDR block is an IP range used with IP-based routing

In Route 53 You can specify CIDR block from /0 to /24 for IPv4 and /0 to /48 for IPv6. For example, a /24 IPv4 CIDR block includes 256 contiguous IP addresses. You can group sets of CIDR blocks (or IP ranges) into CIDR locations, which are in turn grouped into reusable CIDR collections.

DNS query

Usually a request that is submitted by a device, such as a computer or a smart phone, to the Domain Name System (DNS) for a resource that is associated with a domain name. The most common example of a DNS query is when a user opens a browser and types the domain name in the address bar. The response to a DNS query typically is the IP address that is associated with a resource such as a web server. The device that initiated the request uses the IP address to communicate with the resource. For example, a browser can use the IP address to get a web page from a web server. DNS resolver

A DNS server, often managed by an internet service provider (ISP), that acts as an intermediary between user requests and DNS name servers. When you open a browser and enter a domain name in the address bar, your query goes first to a DNS resolver. The resolver communicates with DNS name servers to get the IP address for the corresponding resource, such as a web server. A DNS resolver is also known as a recursive name server because it sends requests to a sequence of authoritative DNS name servers until it gets the response (typically an IP address) that it returns to a user's device, for example, a web browser on a laptop computer.

Domain Name System (DNS)

A worldwide network of servers that help computers, smart phones, tablets, and other IP-enabled devices to communicate with one another. The Domain Name System translates easily understood names such as example.com into the numbers, known as IP addresses, that allow computers to find each other on the internet.

Hosted zone

A container for records, which include information about how you want to route traffic for a domain (such as example.com) and all of its subdomains (such as www.example.com, retail.example.com, and seattle.accounting.example.com). A hosted zone has the same name as the corresponding domain.

Example

The hosted zone for example.com might include a record that has information about routing traffic for www.example.com to a web server that has the IP address 192.0.2.243, and a record that has information about routing email for example.com to two email servers, mail1.example.com and mail2.example.com. Each email server also requires its own record.

IP address

A number that is assigned to a device on the internet—such as a laptop, a smart phone, or a web server—that allows the device to communicate with other devices on the internet. IP addresses are in one of the following formats:

  • Internet Protocol version 4 (IPv4) format, such as 192.0.2.44
  • Internet Protocol version 6 (IPv6) format, such as 2001:0db8:85a3:0000:0000🔡0001:2345

Route 53 supports both IPv4 and IPv6 addresses for the following purposes:

  1. You can create records that have a type of A, for IPv4 addresses, or a type of AAAA, for IPv6 addresses.
  2. You can create health checks that send requests either to IPv4 or to IPv6 addresses.
  3. If a DNS resolver is on an IPv6 network, it can use either IPv4 or IPv6 to submit requests to Route 53.

Name servers

Servers in the Domain Name System (DNS) that help to translate domain names into the IP addresses that computers use to communicate with one another. Name servers are either recursive name servers (also known as DNS resolver) or authoritative name server.

Private DNS

A local version of the Domain Name System (DNS) that lets you route traffic for a domain and its subdomains to Amazon EC2 instances within one or more Amazon virtual private clouds (VPCs).

Record (DNS record)

An object in a hosted zone that you use to define how you want to route traffic for the domain or a subdomain. For example, you might create records for example.com and www.example.com that route traffic to a web server that has an IP address of 192.0.2.234.

Routing policy

A setting for records that determines how Route 53 responds to DNS queries. Route 53 supports the following routing policies:

  1. Simple routing policy – Use to route internet traffic to a single resource that performs a given function for your domain, for example, a web server that serves content for the example.com website.

  2. Failover routing policy – Use when you want to configure active-passive failover.

  3. Geolocation routing policy – Use when you want to route internet traffic to your resources based on the location of your users.

  4. Geoproximity routing policy – Use when you want to route traffic based on the location of your resources and, optionally, shift traffic from resources in one location to resources in another.

  5. Latency routing policy – Use when you have resources in multiple locations and you want to route traffic to the resource that ==provides the best latency=.

  6. IP-based routing policy – Use when you want to route traffic based on the location of your users, and have the IP addresses that the traffic originates from.

  7. Multivalue answer routing policy – Use when you want Route 53 to respond to DNS queries with up to 8 healthy records selected at random.

  8. Weighted routing policy – Use to route traffic to multiple resources in proportions that you specify.

Subdomain

A domain name that has one or more labels prepended to the registered domain name. For example, if you register the domain name example.com, then www.example.com is a subdomain. If you create the hosted zone accounting.example.com for the example.com domain, then seattle.accounting.example.com is a subdomain.

Time to live (TTL)

The amount of time, in seconds, that you want a DNS resolver to cache (store) the values for a record before submitting another request to Route 53 to get the current values for that record. If the DNS resolver receives another request for the same domain before the TTL expires, the resolver returns the cached value.

A longer TTL reduces your Route 53 charges, which are based in part on the number of DNS queries that Route 53 responds to. A shorter TTL reduces the amount of time that DNS resolvers route traffic to older resources after you change the values in a record, for example, by changing the IP address for the web server for www.example.com.

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