Network - Route53 - DNS 101 Flashcards

1
Q

If you’ve used the Internet…

A

…you’ve used DNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

DNS is used to convert…

A

…human friendly domain names into an IP address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

IP addresses are used by…

A

…computers to identify each other on the network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

IP address forms

A

IPv4, IPv6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

IPv6 was created because…

A

…we were running out of IPv4 addresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Top Level Domains - example

A

“.com” in google.com

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Second word in a domain name

A

second level domain name

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Top level domain names controlled by…

A

…Internet Assigned Numbers Authority (IANA) in a root zone database (DB of all available top level domains)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Domain Registrars

A

ensure that domain names aren’t duplicated. Each domain name becomes registered in a central database known as the WhoIS database

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

SOA Records

A

Start of Authority Records

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

SOA Record stores information about…

A
  • the name of the server that supplied the data for the zone
  • the administrator of the zone (contact details, owner name)
  • current version of the data file
  • number of seconds a secondary name server should wait before checking for updates
  • the number of seconds a secondary name server should wait before retrying a failed zone transfer
  • the maximum number of seconds that a secondary name server can use data before it must either be refreshed or expire
  • the default number of seconds for the time-to-live file on resource records
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

NS records

A

stands for Name Server records, used by Top Level Domain servers to direct traffic to the Content DNS server which contains the authoritative DNS records

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A records

A

Address Record. A record used by computer to translate the name of the domain to the IP address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Do ELBs have an IPv4 or IPv6 address?

A

No, they have just a DNS name.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Can you use an A record to resolve to an ELB?

A

No, use an Alias Record

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

TTL record

A

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 in seconds.

17
Q

The lower the TTL…

A

…the faster changes to DNS records take to propagate throughout the internet

18
Q

If adding additional A records, servers to production website or migrate production website to AWS…

A

…DNS change required, will take time to propagate to all end users. Decrease TTL to 300 seconds

19
Q

CNAMES (Canonical Name)

A

resolve one domain name to another

20
Q

Alias Records

A

map record resource sets in your hosted zone to ELBs, CloudFront distributions, or S3 buckets that are configured as websites

21
Q

Key difference between CNAMEs and Alias Records

A

CNAME can’t be used for naked domain names (zone apex). A records or Alias Records can

22
Q

Alias resource record sets can save you time because…

A

…Route53 automatically recognizes changes in the record sets that the alias resource record set refers to

23
Q

Example of how Alias resource record sets can save you time

A

Alias resource record set for example.com points to an ELB at lb1-1234.us-east-1.elb.amazonaws.com. If IP of ELB changes, Route53 will reflect those changes in the DNS answers for example.com w/o any changes to the hosted zone that contains resource record sets for example.com

24
Q

Do ELBs have a pre-defined IPv4 address?

A

No, you resolve to them using a DNS name

25
Q

If you make a request to Route53, CNAMEs…

A

…will be associated w/ a charge. On the other hand, Alias Records won’t