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A Record 📍 — Connects a domain name to an IPv4 address.
AAAA Record 🌱 — Links a domain to an IPv6 address.
CNAME Record 🔗 — Points one domain (an alias) to another canonical domain name.
MX Record 📬 — Directs email traffic by listing mail servers for a domain.
NS Record 📊 — Identifies the authoritative DNS servers for a domain.
PTR Record 🔄 — Does reverse DNS lookup: maps an IP address back to a domain.
TXT Record 📝 — Holds text information, often used for SPF, DKIM, and other security verifications.
SRV Record 🎛️ — Specifies a server and port number for particular services.
SOA Record 📄 — Contains administrative details about the domain’s DNS zone.
CAA Record 🔒 — States which Certificate Authorities (CAs) can issue SSL certificates for the domain.
You Should Know:
1. Querying DNS Records Using Dig (Linux/macOS)
dig example.com A Query A record dig example.com AAAA Query AAAA record dig example.com MX Query MX record dig example.com TXT Query TXT record dig -x 8.8.8.8 Reverse DNS lookup (PTR record)
2. Windows DNS Query with nslookup
nslookup -type=A example.com nslookup -type=MX example.com nslookup -type=TXT example.com nslookup -type=PTR 8.8.8.8
3. Checking DNS Zone Authority
dig example.com NS dig +short example.com SOA
4. Verifying SPF & DKIM Records
dig example.com TXT | grep "v=spf1" dig selector._domainkey.example.com TXT | grep "DKIM"
5. Testing SRV Records
dig _sip._tcp.example.com SRV
- Modifying DNS Records (BIND Zone File Example)
example.com. IN A 192.0.2.1 mail IN MX 10 mail.example.com. www IN CNAME example.com. _dmarc IN TXT "v=DMARC1; p=none; rua=mailto:[email protected]"
7. DNSSEC Validation
dig example.com +dnssec
What Undercode Say:
Understanding DNS records is crucial for network engineers, cybersecurity professionals, and IT administrators. Proper DNS management ensures:
– Faster resolution (A/AAAA records)
– Email deliverability (MX, SPF, DKIM, DMARC)
– Security hardening (CAA, DNSSEC)
– Service discovery (SRV records)
Pro Tip: Always verify DNS propagation after changes using:
dig +trace example.com
For Windows admins, PowerShell offers DNS checks:
Resolve-DnsName example.com -Type A Resolve-DnsName example.com -Type MX
Expected Output:
example.com. 3600 IN A 192.0.2.1 example.com. 3600 IN MX 10 mail.example.com.
Mastering DNS ensures seamless networking, security, and service reliability. 🚀
References:
Reported By: Nasir Amin – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
