OSINT › Module 5 › Lesson 2
dig nslookup and DNS Records YOU Own
NS/A/MX/TXT on example.com or YOUR domain
Visual · dig_dns_owned
dig example.com NS +short. Resolve-DnsName on Windows.
Opening
DNS is the phone book of names you publish. Read your rows before someone else quotes them.
dig, host, nslookup, and PowerShell Resolve-DnsName ask DNS for records. example.com is the safe public example (dig example.com NS +short). YOUR domain replaces example.com when you own it. That is how you confirm NS, A/AAAA, MX, and TXT (SPF/DKIM/DMARC ideas) match what you intended. Original Cyberlium. GATE 192.168.0.1. ViewDNS named for browser views of owned/example names. You will not dig a classmate’s startup, not nmap discovered IPs, not hydra mail hosts. Next: security.txt robots.txt and humans.txt.
1. NS and A: who answers the name, where it points
dig example.com NS +short lists nameservers for the documentation domain. dig example.com A +short shows an address the name currently maps to. On Windows, Resolve-DnsName example.com -Type NS. These commands are literacy. Pointing them at every brand you dislike is not this course.
For YOUR domain, the same commands are a config audit. ; 192.168.0.1 is not a public zone you should “dig” as WHOIS.
Command guide
NS and A: who answers the name, where it points
═══ INSTALL ═══
Linux (Debian/Ubuntu):
Command — copy this
sudo apt install dnsutils
macOS:
Command — copy this
brew install bind
Windows: Built-in: nslookup (or install BIND for dig) Use nslookup (built-in)
═══ LINUX / macOS ═══
Query DNS records
Command — copy this
dig example.com A +short dig example.com NS +short dig example.com MX +short dig example.com TXT +short dig example.com ANY +noall +answer
Alternative tools
Command — copy this
host example.com nslookup example.com nslookup -type=MX example.com
═══ WINDOWS ═══
Command — copy this
nslookup example.com nslookup -type=MX example.com nslookup -type=NS example.com nslookup -type=TXT example.com
Optional command
PowerShell
Command — copy this
Resolve-DnsName example.com Resolve-DnsName example.com -Type MX Resolve-DnsName example.com -Type NS
2. MX and TXT: mail and policy rows you published
MX you met in Module 4. TXT often holds SPF and other policy. Read YOUR domain’s TXT. Do not “collect SPF” from random banks. If you have no domain, example.com TXT is enough literacy.
Unexpected TXT on a name you own can be a leftover vendor or a takeover smell — fix via YOUR DNS host, do not nmap the old vendor.
3. Write the map; do not scan the addresses
Copy NS/A/MX/TXT into your note. An A record is not an invitation to nmap that IP. Cyberlium stops at the record.
Next: well-known text files on a site you own, plus example.com security.txt as literacy, plus a local security.txt in cyberlium-lab.
4. What you ship: NS/A/MX/TXT for example.com and/or YOUR domain, no nmap of A records
dig/host/nslookup/Resolve-DnsName as available. ViewDNS named for owned/example. DEMO GATE. Notes 600.
5. What you record before the next lesson
Date. example.com NS/A. DOMAIN rows or skip. NEVER nmap A. File t12-m05-l02-dig-dns.txt chmod 600.
6. Wrong vs right: strangers vs identifiers YOU own
Worked failure — same OSINT word, opposite target. Right never needs a classmate or a dump site.
Wrong
nmap every A record. dig a classmate startup then hydra SSH. Scan 192.168.0.0/24 “for local DNS.”
Right
Read records. Stop. Next: security.txt robots.txt and humans.txt.
Mission: print DNS rows you are allowed to ask
1) / STOP if router. 2) dig example.com NS +short and A/MX/TXT. 3) Repeat for YOUR domain or skip. Never nmap the addresses. Never classmate zones.
Stuck? Ask Cyberlium AI Mentor
Ask Mentor how NS differs from A — not how to axfr a stranger’s zone.
Knowledge Check
APPLY: In-scope command from this lesson?
Multiple choice
Knowledge Check
APPLY: True or False: An A record is permission to nmap that IP.
True or False
Knowledge Check
APPLY: Windows equivalent named here?
Multiple choice