Checking for live systems:
	
	https://en.wikibooks.org/wiki/Communication_Networks/Ping

	https://en.wikipedia.org/wiki/Ping_sweep

TCP Handshaking:
	
	https://www.geeksforgeeks.org/tcp-flags/

	https://www.geeksforgeeks.org/tcp-3-way-handshake-process/

Port scanning:

	https://en.wikipedia.org/wiki/Port_scanner

	https://nmap.org/book/port-scanning-tutorial.html

	https://www.softwaretestinghelp.com/port-scanners/

	https://securitytrails.com/blog/best-port-scanners

Banner Grabbing:

	https://en.wikipedia.org/wiki/Banner_grabbing

	https://www.hackingarticles.in/5-ways-banner-grabbing/

	http://www.cybersecuri7y.com/2017/06/banner-grabbing-tools.html

Bypass firewalls:

	https://nmap.org/book/firewall-subversion.html

	https://nmap.org/nsedoc/scripts/firewall-bypass.html

	https://security.stackexchange.com/questions/117772/using-nmap-to-bypass-a-firewall-and-perform-os-fingerprinting

	https://www.youtube.com/watch?v=d5-wBkMRPQU

Vulnerability Scanning:

	https://www.qualys.com/

	https://cwatch.comodo.com/blog/website-security/top-10-vulnerability-assessment-scanning-tools/

	https://owasp.org/www-community/Vulnerability_Scanning_Tools

	https://www.dnsstuff.com/network-vulnerability-scanner

	https://www.qualys.com/

	https://www.acunetix.com/vulnerability-scanner/

Network Mapping:

	https://www.manageengine.com/network-monitoring/network-mapping.html?network=g&device=c&keyword=network%20mapper&campaignid=9127733432&creative=414467774097&matchtype=e&adposition=&placement=&adgroup=92424189276&targetid=kwd-111650537&gclid=Cj0KCQjwjcfzBRCHARIsAO-1_Oq79intVPzwfM4JHbU5lx7VGM3NkXKVgbAmGtEXp1LfkNzg-jgd_nkaAu8HEALw_wcB

	https://www.solarwinds.com/network-topology-mapper

	https://www.spiceworks.com/free-network-mapping-software/

	https://en.wikipedia.org/wiki/Network_mapping

	https://www.10-strike.com/lanstate/download.shtml

Countermeasures:

	https://www.w3schools.in/ethical-hacking/scanning-techniques/#Countermeasures_Against_Scanning

	https://www.softwaretestinghelp.com/intrusion-detection-systems/

	https://resources.infosecinstitute.com/network-design-firewall-idsips/#gref

	https://www.esecurityplanet.com/products/top-intrusion-detection-prevention-systems.html

	https://www.port80software.com/products/servermask/try

	https://pagexchanger.soft112.com/