Understanding Nmap Basics
What is Nmap?
Nmap (Network Mapper) is a powerful open-source tool used for network discovery and security auditing. It is widely used by cybersecurity professionals to scan and analyze networks, identify active hosts, and detect potential vulnerabilities.
Nmap Basics
Nmap provides a variety of scan types, including TCP connect scans, SYN scans, UDP scans, and more. The basic syntax for running an Nmap scan is:
nmap [Scan Type Options] [Target Specification] [Output Options]
For example, to perform a basic TCP connect scan on a target host, you can use the following command:
nmap 192.168.1.100
This will scan the target host at the IP address 192.168.1.100
and display the open ports and running services.
Nmap Scan Types
Nmap offers a wide range of scan types to suit different use cases. Some common scan types include:
- TCP Connect Scan (
-sT
)
- SYN Scan (
-sS
)
- UDP Scan (
-sU
)
- Idle/Zombie Scan (
-sI
)
- Comprehensive Scan (
-sC
)
Each scan type has its own advantages and tradeoffs, such as speed, stealth, and accuracy. The choice of scan type depends on the specific requirements of the network reconnaissance task.
Nmap Output and Reporting
Nmap can generate detailed reports on the scanned hosts, including information about open ports, running services, operating systems, and potential vulnerabilities. The output can be saved in various formats, such as XML, grepable, and normal.
nmap -oA myscan 192.168.1.100
This command will perform a comprehensive scan on the target host and save the results in three different formats: myscan.nmap
, myscan.gnmap
, and myscan.xml
.