https://ceh.brutef0rce.
com/enumeration
DNS Enumeration:
https://www.hackingarticles.in/4-ways-dns-enumeration/
https://securitytrails.com/blog/dns-enumeration
https://en.wikipedia.org/wiki/DNS_zone_transfer
NetBIOS and SMB Enumeration:
https://www.youtube.com/watch?v=sXqT95eIAjo
http://nbtenum.sourceforge.net/
https://www.hackingarticles.in/netbios-and-smb-penetration-testing-on-
windows/
https://www.hackingarticles.in/smb-penetration-testing-port-445/
https://tools.kali.org/information-gathering/enum4linux
SNMP Enumeration:
https://www.hackingarticles.in/snmp-lab-setup-and-penetration-testing/
LDAP Enumeration:
https://github.com/CroweCybersecurity/ad-ldap-enum
https://medium.com/@Shorty420/enumerating-ad-98e0821c4c78
https://n0where.net/ldap-based-active-directory-enumeration
https://www.hackingarticles.in/lightweight-hack-the-box-walkthrough/
https://www.hackingarticles.in/penetration-testing-windows-server-active-
directory-using-metasploit-part-1/
NTP Enumeration:
https://www.oreilly.com/library/view/ethical-hacking-pro/200000006A0417/
N00007.html
https://www.zerosuniverse.com/ethical-hacking/what-is-ntp-enumeration/
http://www.ethicaloverflow.com/m2%20enumeration.php
https://nmap.org/nsedoc/scripts/ntp-info.html
SMTP Enumeration:
https://www.hackingarticles.in/4-ways-smtp-enumeration/
https://www.peerlyst.com/posts/smtp-enumeration-technique-hamza-m-hirsi
https://tools.kali.org/information-gathering/smtp-user-enum
https://nmap.org/nsedoc/scripts/smtp-enum-users.html
http://pentestmonkey.net/tools/user-enumeration/smtp-user-enum
Enumeration Countermeasures:
http://etutorials.org/Networking/network+security+assessment/Chapter+3.+Internet+Ho
st+and+Network+Enumeration/3.5+Enumeration+Countermeasures/
http://luizfirmino.blogspot.com/2011/09/enumeration-countermeasures.html