Route 53 Flashcards
What Is DNS?
DNS stands for “Domain Name System.” It’s like the internet’s phone book – a system that translates human-friendly domain names (like www.example.com) into the numerical IP addresses that computers use to identify each other on the internet.
What is Top-Level Domain?
If we look at common domain names (e.g., google.com, bbc.co.uk, and acloud.guru), you will notice a string of characters separated by dots (periods).
The last word in a domain name represents the top-level domain.
The second word in a domain name is known as a second-level domain
name (this is optional, though, and depends on the domain name).
- Are controlled by the Internet Assigned Numbers Authority (IANA)
What are Domain Registrars?
A registrar is an authority that can assign domain names directly under one or more top-level domains.
These domains are registered with InterNIC, a service of ICANN, which enforces the uniqueness of domain names across the internet.
What is a SOA record?
SOA stands for “Start of Authority.” In DNS, the SOA record is a crucial record type that provides essential information about a particular domain. It serves as the starting point for managing the domain’s DNS settings.
What are NS records?
NS records are used by top-level domain servers to
direct traffic to the content DNS server that contains
the authoritative DNS records.
What Is an A Record?
An A (or address) record is the fundamental type of
DNS record.
The A record is used by a computer to translate
the name of the domain to an IP address.
For example, http://www.google.com
might point to http://123.10.10.80
What Is a TTL?
The length that a DNS record is cached on either the resolving server or the user’s own local PC is equal to the value of the time to live (TTL) in seconds.
The lower the time to live, the faster changes to DNS records take to propagate throughout the internet.
What Is a CNAME?
A CNAME (canonical name) can be used to resolve one domain name to another. For example, you may have a mobile website with the domain name http://m.acloud.guru that is used when users browse your domain name on their mobile devices.
A CNAME cannot be used to point to naked domain names(catagram.io).
What are Alias Records?
Alias records are used to map resource record sets in your hosted zone to load balancers,CloudFront distributions, or S3 buckets that are configured as websites.
Alias records work like a CNAME record in that you can map one DNS name (www.example.com) to another “target” DNS name (elb1234.elb.amazonaws.com).
CNAME vs Alias Records
CNAME records are used to alias one domain name to another, typically for subdomains, while Alias records are specific to AWS services and are used to map a domain or subdomain to an AWS resource, supporting both root domains and subdomains.
A CNAME cannot be used to point to naked domain names(catagram.io).
No charge for alias records pointing at AWS resources.
What Is Route 53?
Route 53 is Amazon’s DNS service.
It allows you to register domain names, create
hosted zones, and manage and create DNS
records.
Route 53 is named after Route 66 (one of the
original highways across the United States) but is
called 53 because DNS operates on port 53.
Name the 7 Routing Policies Available with Route 53?
- Simple Routing
- Weighted Routing
- Latency-Based Routing
- Failover Routing
- Geolocation Routing
- Geoproximity Routing
(Traffic Flow Only) - Multivalue Answer Routing
Explain the Simple Routing Policy.
If you choose the simple routing policy, you can only have one record with multiple IP addresses.
If you specify multiple values in a record, Route 53 returns all values to the user in a random order.
Does not support health checks.
What are Health Checks in Route 53?
- You can set health checks on individual record sets.
- If a record set fails a health check, it will be removed from Route 53 until it passes the health check.
-You can set SNS notifications to alert you about failed health checks. - If more than 18% of the health checkers report as healthy then it is considered healthy.
Explain the Weighted Routing Policy.
Allows you to split your traffic based on different weights assigned.
For example, you can set 10% of your traffic to go to us-east-1 and 90% to go to eu-west-1. Includes health checks.
Good for simple load balancing or when testing new software.
if an unhealthy record is selected the process is repeated until a healthy record is selected.
Explain Geoproximity Routing Policy.
- Returns the closest distance.
- Geoproximity routing lets Amazon Route 53 route traffic to your resources based on the geographical location of your users and your resources.
- You can also optionally choose to route more traffic or less to a given resource by specifying a value, known as a bias. A bias expands or shrinks the size of the geographic region from which traffic is routed to a resource.
- To use geoproximity routing, you must use Route 53 traffic flow.
