Basic Nmap Scans and Configurations

A SYN “Half-open” Scan is a network scan command that can gather TCP port information from a target computer in a stealth manner.

A UDP Scan is a network scan command that can identify open UDP ports on a target computer.

Network scans can identify network mapping information, OS on the network, unfiltered ports, hosted services, and more.

A Ping Sweep is a network scan command that can scan a complete network range to identify computers present on a network.

A TCP Scan is a network scan command that can gather TCP port information from a target computer.

Network Discovery and Security Audits are why cybersecurity professionals prefer Nmap scans.

A basic Nmap scan is TCP Connect Scans (-sT), SYN “Half-open” Scans (-sS), and Ping Sweep.

Cybersecurity professionals should be aware of these three basic commands to perform network scans in Nmap:

• Ping Sweep,
• TCP Connect Scans (-sT),
• SYN “Half-open” Scans (-sS).

When performing Nmap scans, the user must understand the target and why they are scanning the system.

Modern cyber law(s) and regulations define how scans may be performed legally.

Some obstacles that may be encountered when scanning a system are:

• firewalls
• proxies
• IDS/IPS

The types of scans you can do using Nmap are categorized by protocol or packet type.

Nmap configuration options are organized feature capabilities: target specification, host discovery, scan techniques, port specification, scan order, service/version detection, script scans, OS detection, timing and performance, firewall/IDS evasion, spoofing, misc., and output.

In Nmap, -sP is a configuration option that can perform a “ping sweep.”

In Nmap, -sT is a configuration option that can initiate a TCP connect scan.

When performing Nmap scan, configuration options can be used to change the scope of the scan, add complexity to a scan, and define granular specifications.