What is DNS?

The Domain Name System (DNS) acts like the Internet's phonebook. It translates easy-to-remember domain names (like youtube.com) into IP addresses (like 172.217.194.93) that computers use to locate each other on the Internet.

Without DNS, you'd have to memorize numeric IPs instead of simply typing "google.com" in your browser.

Types of DNS Records

Common DNS record types include:

• A – Maps a domain to an IPv4 address
• AAAA – Maps a domain to an IPv6 address
• CNAME – Alias of one domain to another
• MX – Specifies email servers for a domain
• NS – Lists the name servers for the domain
• TXT – Stores human-readable text, often used for verification (e.g., SPF, DKIM)

Try It Yourself: Python DNS Lookup

You can run this Python script in your own environment to see DNS records for a domain:

import dns.resolver

domain = "google.com"  # Replace with any domain
record_types = ["A", "AAAA", "CNAME", "MX", "NS", "TXT"]

for rtype in record_types:
    try:
        answers = dns.resolver.resolve(domain, rtype)
        print(f"\n{rtype} Records:")
        for rdata in answers:
            print(" ", rdata.to_text())
    except Exception as e:
        print(f"\n{rtype}: Error:", e)
        

This script uses the dnspython library. Install it with pip install dnspython if needed.

DNS in Cybersecurity

• DNS Spoofing: Attackers trick DNS resolvers into returning malicious IPs
• DNS Tunneling: Data can be exfiltrated using DNS requests
• Threat Intelligence: Monitoring DNS patterns helps detect suspicious activity
• DNS Filtering: Blocking malicious domains at the DNS layer improves security