2.6 - DNS Configuration Flashcards
What is DNS?
DNS is the domain name system that converts fully qualified domain names into IP addresses.
Is DNS a standalone server?
No, DNS is a distributed system with multiple servers across the internet working on a hierarchy.
How many root server clusters are there?
There are 13 root server clusters, consisting of over 1,000 different servers.
What are generic top-level domains?
These are domains like .com, .org, .net, etc.
What are country-level top-level domains?
Domains specific to countries, like .us (USA), .ca (Canada), and .uk (UK).
What does the dot at the end of a domain name represent?
The dot at the end designates the end of a fully qualified domain name.
What is an example of a hierarchical domain structure?
For example, www.professormesser.com with mail.professormesser.com for mail servers.
What command can you use to see DNS translation results?
The dig command can be used, e.g., ‘dig www.professormesser.com’.
What does the ANSWER SECTION in dig command results show?
It shows the IP addresses associated with the requested domain name.
What is nslookup?
A command to query DNS servers for IP addresses, similar to dig.
What are resource records in DNS?
These are records like IP addresses, certificates, host names, etc., used in DNS.
Why are DNS servers critical?
DNS servers translate domain names into IP addresses; without them, websites can’t be accessed.
What is an A record?
An address record mapping a fully qualified domain name to an IPv4 address.
What is a quad A record?
An address record mapping a fully qualified domain name to an IPv6 address.
What is an MX record?
A mail exchanger record specifying where emails for a domain should be delivered.
What is a TXT record?
A text record in DNS used for purposes like verification and email security.
What is an SPF record?
A Sender Policy Framework record listing authorized email servers for a domain.
What is a DKIM record?
A Domain Keys Identified Mail record that provides a digital signature for outgoing emails.
What is DMARC?
Domain-based Message Authentication, Reporting, and Conformance; it specifies what to do with unverified emails.
What does a DMARC record specify?
It specifies actions like accepting, spamming, or rejecting unverified emails, and where to send reports.
