Nmap is a network connection scanning software used to scan the network connection end opened by online computers. Determine which services are running on which terminals and infer which operating system the computer is running. It is one of the necessary software for network administrators and is used to evaluate the security of network systems. The common nmap commands in work are as follows:
1. Install nmap Software
[Root @ CentOS yum. repos. d] # yum install nmap
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package nmap. i686. 51-2.el6 will be installed
--> Processing Dependency: libpcap. so.1 for package: 2: nmap-5.51-2.el6.i686
--> Running transaction check
---> Package libpcap. i686 14. 0.0-6.20091201git117cb5.el6 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
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Package Arch Version Repository Size
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Installing:
Nmap i686. 51-2.el6 c6-media 2.7 M
Installing for dependencies:
Libpcap i686 14. 0.0-6.20091gitgit117cb5.el6 c6-media 125 k
Transaction Summary
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Install 2 Package (s)
Total download size: 2.9 M
Installed size: 10 M
Is this OK [y/N]: y -- confirm Installation
2. Common options
-ST -- TCP protocol Scan
-SS -- TCP Synchronous Scan
-SP -- Ping to check whether the host is running
-SU -- UDP Port Scan
-SA-can penetrate the firewall rule set
-V-detailed information about the scanning process
-P port range -- scan the specified port range
-IL file -- the target can be read from the file.
-ON -- rewrite the scan result to a file
3. Use of tools
[Root @ centos/] # nmap-sP 192.168.1.0/24 -- check the number of hosts in
[Root @ centos/] # nmap-sT 192.168.1.23 -- scan the TCP port of the specified host
[Root @ centos/] # nmap-sS 192.168.1.23 -- SYN scans IP tcp and udp ports (FAST)
[Root @ centos/] # nmap-O 192.168.1.23 -- view the operating system corresponding to the IP address
[Root @ centos/] # nmap-A 192.168.1.23 -- view the detailed operating system corresponding to the IP address
[Root @ centos/] # nmap-sA 192.168.1.23 -- ACK Scan can penetrate the Firewall
[Root @ centos/] # nmap-PS 192.168.1.23 -- view the port opened on the target host
[Root @ centos/] # nmap-PS-p 3306, 100 2.2.2.1--- view the specified IP address and the specified port
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