2.6 DNS Configuration

Question 1

There are hundreds of generic top-level domains. What are top-level domains?

Answer 1

.com, .org, .net, etc

Question 2

There are over 275 country code top-level domains. What are country code top-level domains?

Answer 2

.uk, .us, .ca, etc

Question 3

How many DNS root server clusters are there?

Answer 3

13 root server clusters (over 1,000 actual servers)

Question 4

What is DNS hierarchy?

Answer 4

DNS follows a path

www.
professormesser
.org

Question 5

What are DNS records called?

Answer 5

Resource Records (RR)

Question 6

What are RR for DNS?

Answer 6

resource records, the database records of domain name services

Question 7

There are over ___ DNS record types

Answer 7

over 30 record types

(IP addresses, certificates, host alias names, etc)

Question 8

DNS records are ____

Answer 8

important and critical configurations!

(check settings, backup, test)

Question 9

What are DNS Address records?

Answer 9

Defines the IP address of a host (most popular query)

Question 10

What are the 2 types of DNS Address records?

Answer 10

1. A
2. AAAA

Question 11

What’s the difference between the 2 DNS Address record types?

Answer 11

A - for IPv4 addresses (modify this to change hostname to IP address resolution)
AAAA - for IPv6 addresses (same DNS server, different records)

Question 12

What does MX record mean?

Answer 12

Mail exchanger record

Question 13

What is an MX record?

Answer 13

determines the hostname for the mail server (not the IP address, the name)

Question 14

What are Text records (TXT)?

Answer 14

Useful public information in human-readable text commonly used for email security like verification of domain ownership

(external email servers validate information from your DNS)

Question 15

What is Sender Policy Framework (SPF)?

Answer 15

SPF protocol - a list of all servers authorized to send emails for a domain to prevent mail spoofing

(mail servers perform a check to see if incoming mail really did come from an authorized host)

Question 16

What does DKIM stand for?

Answer 16

Domain Keys Identified Mail

Question 17

What does DKIM do?

Answer 17

Domain Keys Identified Mail

Digitally signing a domain’s outgoing mail (public key is in a DKIM TXT record)

Question 18

What does DMARC stand for?

Answer 18

Domain-based Message Authentication, Reporting, and Conformance

Question 19

What is DMARC for?

Answer 19

validates emails and prevents unauthorized email use (spoofing) as an extension of SPF and DKIM

(you can decide what to do with emails that don’t validate through SPF or DKIM)

Question 20

What does SPF stand for?

Answer 20

Sender Policy Framework