Network security

query WHOIS servers

whois webpage

Passive Reconnaissance with nslookup

nslookup -type=(A/AAAA/TXT/MX…) website DNS_server

passive reconnaissance with dig

dig website DNS_server type

What is ARP?

Address Resolution Protocol, mapping IPaddress with MAC address

What is ICMP?

"Internet Control Message Protocol: used for diagnostics and error reporting in networks;

It helps check if a host (computer/server) is alive and reachable."

What is TCP?

Transmission Control Protocol: a connection-based protocol that ensures data arrives correctly and in order, 3 ways handshake

What is UDP?

User Datagram Protocol:

What address is used to identify the start of a network?

network address

What address is used to identify devices within a network?

host address

ARP Scan

sudo nmap -PR -sn MACHINE_IP/24

ICMP Echo Scan

sudo nmap -PE -sn MACHINE_IP/24

ICMP Timestamp Scan

sudo nmap -PP -sn MACHINE_IP/24

ICMP Address Mask Scan

sudo nmap -PM -sn MACHINE_IP/24

TCP SYN Ping Scan

sudo nmap -PS22,80,443 -sn MACHINE_IP/30

TCP ACK Ping Scan

sudo nmap -PA22,80,443 -sn MACHINE_IP/30

UDP Ping Scan

sudo nmap -PU53,161,162 -sn MACHINE_IP/30

optionno DNS lookup

-n

optionreverse-DNS lookup for all hosts

-R

optionhost discovery only

-sn