2.6 DNS Flashcards
What does DNS stand for?
Domain Name System.
What is the primary function of DNS?
Translates human-readable domain names into IP addresses.
Why is DNS important for internet browsing?
It allows users to access websites using names instead of numerical IP addresses.
What is the hierarchical structure of DNS?
Root Level → TLDs → Second-Level Domains → Subdomains → Hosts.
What does a TLD (Top-Level Domain) represent?
The last part of a domain name (e.g., .com, .org, .edu, .gov, .uk).
What is a second-level domain?
The main domain name (e.g., diontraining in diontraining.com).
What is a subdomain?
A prefix to a domain name (e.g., mail.diontraining.com or www.google.com).
What is an A record in DNS?
Maps a domain name to an IPv4 address.
What is an AAAA record in DNS?
Maps a domain name to an IPv6 address.
What is a CNAME record?
An alias that redirects one domain name to another.
What is an MX record used for?
Directs email traffic to the correct mail server for a domain.
What is a TXT record in DNS?
Stores text-based data, often used for domain verification and email security.
What is an NS record?
Identifies the authoritative name server for a domain.
What is SPF in DNS?
Sender Policy Framework, used to prevent email spoofing.
What is DKIM in DNS?
DomainKeys Identified Mail, which authenticates email using encryption.
What is DMARC in DNS?
Domain-Based Message Authentication, Reporting & Conformance, used to enforce SPF and DKIM for email security.
What is the difference between recursive and iterative DNS lookups?
Recursive lookups get the full answer from the DNS server, while iterative lookups require the client to query multiple servers.
What does TTL (Time to Live) in DNS define?
The amount of time a DNS record is cached before it needs to be refreshed.
How does DNS caching help internet performance?
It reduces DNS lookup time and network traffic by storing frequently accessed domain mappings.
What happens if a DNS record has a low TTL?
It refreshes more frequently, ensuring up-to-date information but increasing DNS traffic.
What does an authoritative DNS server do?
Provides the final answer for a domain’s IP address.
What is a DNS resolver?
A server that processes DNS queries and retrieves the required IP addresses.
What is a root DNS server?
The top-level DNS server that helps direct queries to the correct TLD name servers.
What are common DNS troubleshooting commands?
nslookup, dig, ping, traceroute.