Skip to main content

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

Labels:

Popular posts from this blog

Windows 10 1903 Critical Error: Your Start menu isn't working

Windows 10 1903 Critical Error: Your Start menu isn't working. We'll try to fix it the next time you sign in.
Read more

[PowerShell]: Powershell script uploading backup databases to ftp server

Author:  Enrique Puig Nouselles http://gallery.technet.microsoft.com/scriptcenter/80647f66-139c-40a4-bb7a-04a2d73d423c Nhu cầu - Học sử dụng Powershell và áp dụng vào thực tế - Server chạy MS SQL được backup mỗi ngày và lưu các file backup ở folder mặc định "C:/Program Files/Microsoft SQL Server/MSSQL11.MSSQLSERVER/MSSQL/Backup" - Upload các file database backup về một ftp server khác để lưu "offsite" # Begin script # Thanks to: Enrique Puig Nouselles http://gallery.technet.microsoft.com/scriptcenter/80647f66-139c-40a4-bb7a-04a2d73d423c # Khai báo folder chứa các file backup database, dưới đây là folder backup mặc định của MS SQL 2012 $Dir="C:/Program Files/Microsoft SQL Server/MSSQL11.MSSQLSERVER/MSSQL/Backup"   # ftp server $ftp = "ftp://IPAddres/subfolder/subsubfolder" $user = "usernamehere" $pass = "passwordhere" # DO NOT use $(Get-Date), use $d variable instead, otherwise SQL Agent gets error "The...
Read more