Practical 1

Aim: To learn TCP scanning using Nmap

What is TCP?

TCP (Transmission Control Protocol) is a core protocol of the Internet Protocol Suite. It ensures reliable, ordered, and error-checked delivery of data between applications over an IP network.

What is Nmap?

Nmap (Network Mapper) is an open-source tool for network exploration and security auditing. It scans IP addresses and ports to identify live hosts, services, and vulnerabilities.

List of Best Port Scanning Tools

Cross-Platform (Windows & Linux)	Windows-Only	Linux-Only	Online Scanners
Nmap	Advanced IP Scanner	Netcat (nc)	Shodan
Masscan		Hping3	Pentest-Tools Port Scanner
Unicornscan			YouGetSignal
RustScan			IPVoid Port Scanner
Angry IP Scanner

TCP Scanning

TCP scanning determines which TCP ports on a target are open, closed, or filtered.

Nmap Scan Commands

Basic Scans

# Basic TCP Connect Scan
nmap [TARGET_IP]
# Example:
nmap 192.168.1.1

# SYN Scan (Stealth/Half-Open)
nmap -sS [TARGET_IP]
# Example:
nmap -sS 192.168.1.1

# Full TCP Connect Scan
nmap -sT [TARGET_IP]
# Example:
nmap -sT 192.168.1.1

Advanced Scans

# Service Version Detection
nmap -sV [TARGET_IP]
# Example:
nmap -sV 192.168.1.1

# OS Detection
nmap -O [TARGET_IP]
# Example:
nmap -O 192.168.1.1

# Aggressive Scan (OS + Version + Scripts + Traceroute)
nmap -A [TARGET_IP]
# Example:
nmap -A 192.168.1.1

# SYN + OS + Version
nmap -sS -O -sV [TARGET_IP]
# Example:
nmap -sS -O -sV 192.168.1.1

Stealth Scans

Scan Type	Command	Description
FIN Scan	`nmap -sF [TARGET]`	Sends FIN; open ports ignore, closed send RST
Xmas Scan	`nmap -sX [TARGET]`	FIN+URG+PUSH flags set
ACK Scan	`nmap -sA [TARGET]`	Determines filtered/unfiltered
Window Scan	`nmap -sW [TARGET]`	Uses TCP window size
Maimon Scan	`nmap -sM [TARGET]`	FIN+ACK probe

UDP Scanning

nmap -sU [TARGET]
nmap -sU -sV [TARGET]  # With version detection

Scan Targeting

# Specific ports
nmap -p 80,443 [TARGET]

# All ports
nmap -p- [TARGET]

# Port range
nmap -p 1-1000 [TARGET]

# Top N ports
nmap --top-ports 100 [TARGET]

Script Scanning (NSE)

nmap -sC [TARGET]                    # Default scripts
nmap --script http-vuln-cve2014-0160 [TARGET]  # Specific script

Output Options

nmap -oX scan_results.xml [TARGET]   # XML
nmap -oN scan_results.txt [TARGET]   # Normal
nmap -oG scan_results.gnmap [TARGET] # Grepable

Timing & Performance

nmap -T4 [TARGET]   # Fast
nmap -T1 [TARGET]   # Slow/Stealth

Multiple Targets

nmap 192.168.1.1-100
nmap -iL targets.txt

How to Install Zenmap (GUI for Nmap)

Windows

Download: https://nmap.org/download.html
Run .exe installer → Includes Nmap + Zenmap
Launch: Start Menu → Zenmap GUI

Linux (Ubuntu/Debian)

sudo apt update
sudo apt install zenmap

Note: Zenmap is deprecated in newer distros. Use .deb from nmap.org/dist/ if needed.

macOS

Zenmap not supported. Use CLI Nmap or third-party GUIs (e.g., NmapSI4).

Practical 1

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