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DNS: Notes

DNS Root Servers

Domain Name System

DNS uses UDP port 53 as default and TCP port 53 as fallback.

nslookup

nslookup -type=txt youtube.com
nslookup -type=mx google.com

dig

dig youtube.com txt

host - DNS lookup utility

host -t txt google.com

Check PTR text record

PS C:\Users\Administrator> nslookup -type=ptr 173.82.240.78
Server:  UnKnown
Address:  2402:800:20ff:6666::1

Non-authoritative answer:
78.240.82.173.in-addr.arpa      name = mx2.practicehabits.net
PS C:\Users\Administrator>

Check DMARC text record

PS C:\Users\Administrator> nslookup -type=txt _dmarc.practicehabits.net
Server:  UnKnown
Address:  2402:800:20ff:6666::1

Non-authoritative answer:
_dmarc.practicehabits.net       text =

        "v=DMARC1; p=reject; rua=mailto:postmaster@practicehabits.net, mailto:postmaster@practicehabits.net"
PS C:\Users\Administrator> nslookup -type=txt _dmarc.2practice.xyz
Server:  UnKnown
Address:  2402:800:20ff:6666::1

*** No text (TXT) records available for _dmarc.2practice.xyz

Online tools

https://mxtoolbox.com/

https://ViewDNS.info/

DMARC Record Checker

DKIM Record Checker

DNS History Lookup

References

Practice

>>> THM | DNS Manipulation

>>> THM | DNS in Details

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