AWS Route 53

Question 1

Why is it called Route 53?

Answer 1

DNS runs on port 53 and the first interstate in the USA was Route 66. Thus, Route 53.

Question 2

What is DNS?

Answer 2

Domain Name Servers are conceptually similar to phone books and convert human friendly domain names such as http://acloud.guru to IP addresses such as http://82.124.53.1

Question 3

IPv4

Answer 3

32 bit addresses that is limited to just over 4 billion total addresses. (4,294,967,296)

Question 4

IPv6

Answer 4

Created to solve the depletion issue with IPv4. 128 bit addresses that allow for over 340 undecillion addresses (36 zeroes).

Question 5

What controls Top Level Domains?

Answer 5

Top Level Domains are controlled by the Internet Assigned Numbers Authority (IANA). They are held in a root database: http://www.iana.org/domains/root/db

Question 6

What is the Top Level Domain?

Answer 6

The Top Level Domain is the last part of a web address. For example: .com, .edu, .gov, etc.

Question 7

What is a Domain Registrar?

Answer 7

Domain names are registered with Domain Registrars such as Amazon and GoDaddy. InterNIC enforces the uniqueness of domain names on the internet and each domain name is registered in a central WhoIS database.

Question 8

What is a Start Of Authority Record?

Answer 8

An SOA Record stores information about the name of the server that supplied the data for the zone, the zone administrator, current data file version and time-to-live file.

Question 9

What are Name Server Records?

Answer 9

NS Records are used by Top Level Domain servers to direct traffic to the Content DNS server that contains the authoritative DNS records.

Question 10

What is an “A” record?

Answer 10

An “A” record is the fundamental DNS record. The “A” stands for address and is used by a computer to translate the domain name to an IP address.

Question 11

What is TTL?

Answer 11

Time-To-Live is the length of time in seconds that a record is cached on either the Resolving Server or the user’s local PC. The default is often 48 hours.

Question 12

What is a CNAME?

Answer 12

CNAME stands for Canonical Name and is used to resolve one domain name to another domain name.

Question 13

Can you use a CNAME for a naked domain name?

Answer 13

No! A CNAME must be used for either an A record or an Alias.

Question 14

Do Elastic Load Balancers have a pre-defined IPv4 address?

Answer 14

No! You resolve to them using a DNS name.

Question 15

Can you buy domain names directly from AWS?

Answer 15

Yes!

Question 16

How long does it take to register a domain?

Answer 16

I can take up to three days.

Question 17

What routing policies are available with Route 53?

Answer 17

• Simple Routing
• Weighted Routing
• Latency-based Routing
• Failover Routing
• Geolocation Routing
• Geoproximity Routing (Traffic Flow Only)
• Multivalue Answer Routing

Question 18

What does the Simple Routing Policy do?

Answer 18

Simple Routing will essentially randomly distribute traffic to different servers under one DNS name based on IP addresses provided.

Question 19

What does the Weighted Routing Policy do?

Answer 19

Weighted Routing allows you to split traffic between servers based on weights assigned. For instance, you could send 10% of traffic to server 1 and 90% of traffic to server 2.

Question 20

What happens when a DNS record set fails a health check?

Answer 20

The record will be removed from Route 53 until it passes the health check.

Question 21

What does Latency-based Routing do?

Answer 21

Traffic is routed to whichever server will provide the server with the lowest latency.

Question 22

What does Failover Routing do?

Answer 22

Failover Routing allows you to set up an active/passive setup. If the active site fails a health check, it will divert traffic to the secondary site.

Question 23

What does Geolocation Routing do?

Answer 23

Geolocation Routing allows you to specify where traffic will be sent based on the user’s geographic location (That is, the location where a DNS query originates).

Question 24

What does Geoproximity Routing (Traffic Flow Only) do?

Answer 24

Geoproximity Routing lets Route 53 route traffic to your resources based on the geographic location of your users AND your resources.

Question 25

What does the Multivalue Answer Policy do?

Answer 25

It allows you to configure Route 53 to return multiple values in response to DNS queries. You can set health checks so that only healthy values are returned. Basically Simple Routing, with the addition of health checks.