CompTIA A+ 1101 DNS & DNS Records

Question 1

• translates human-readable domain names into computer-readable IP addresses
• made of multiple, hierchial servers
• distributed database

Answer 1

Domain Name System (DNS)

Question 2

• database records of DNS
• over 30 record types

Answer 2

Resource Records (RR)

Question 3

A Records:
- IPv4
- modify to change the host name to IP address resolution

AAAA Records:
- IPv6
- the same DNS server, different records (modify to change the host name to IP address resolution)

Answer 3

Address Records (A) (AAAA)

Question 4

determines the host name for the mail server

Answer 4

Mail Exchanger Records (MX)

Question 5

• human-readable text information
• useful public information
• can be used for verification purposes or email security
• use “dig [website name] txt” in cmd prompt to view (or, “nslookup -type=txt [website name/domain name]” when dig isn’t available)

Answer 5

Text Records (TXT)

Question 6

specifies how long an end station will remember the match between a fully qualifies domain name and IP address

Answer 6

Time To Live (TTL)

Question 7

• a list of all the email servers that are authorized to send messages using your fully qualified domain name
• prevents spoofing (mail servers perform a check to see if incoming mail really did come from an authorized host)

Answer 7

Sender Policy Framework (SPF)

Question 8

• digitally signs a domain’s outgoing mail
• valuated by mail servers (not usually seen by the end-user)
• the public key is stored in the DKIM TXT record

Answer 8

Domain Keys Identified Mail (DKIM)

Question 9

• prevents unauthorized email use and spoofing
• an extension of SPF and DKIM
• takes the extra step to determine the disposition that should be used when someone receives a message that cannot be validated

Answer 9

Domain-Based Message Authentication, Reporting, and Conformance (DMARC)