Nmap是一个用于网络探索和安全审计的开源工具。它被设计用来快速扫描大型网络，尽管它在单主机上运行良好。
Nmap支持在Windows、Unix/Linux以及MAC OS平台下运行。它的设计目标是快速地扫描大型网络，当然用它扫描单个主机也没有问题。Nmap以新颖的方式使用原始IP报文来发现网络上有哪些主机、那些主机提供什么服务（应用程序名和版本）、那些服务运行在什么操作系统（包括版本信息）、它们使用什么类型的报文过滤器/防火墙，以及一堆其它功能。
NMAP是一款流行的网络扫描和嗅探工具也是一个强大的端口扫描类安全测评工具，被广泛应用在安全扫描，nmap是一个好用的网络工具，在生产和开发中也经常用到，主要做端口开放性检测和局域网信息的查看收集等，不同Linux发行版包管理中一般也带有nmap工具。
官网下载源码包进行编译安装
[https://namp.org/](https://namp.org/)
http://www.nmap.com.cn/
root@yalong-:~# apt-get install nmap
root@yalong:~# man nmap
root@yalong:~# nmap --help
针对本机进行扫描，检测开放了哪些常用的TCP端口、UDP端口
root@yalong:~# nmap 127.0.0.1
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:43 CST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000032s latency).
Not shown: 998 closed ports
PORT STATE SERVICE
22/tcp open ssh
631/tcp open ipp
Nmap done: 1 IP address (1 host up) scanned in 1.69 seconds
扫描结果中，STATE列若为 open 则表示开放状态，为 filtered 表示可能被防火墙过滤，为 closed 表示端口为关闭状态。
检测网段中哪些主机提供FTP服务
root@yalong:~# nmap -p 21 192.168.1.0/24
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:50 CST
Nmap scan report for _gateway (192.168.1.1)
Host is up (0.0042s latency).
PORT STATE SERVICE
21/tcp closed ftp
MAC Address: YY (Huawei Technologies)
Nmap scan report for 192.168.1.2
Host is up (0.047s latency).
PORT STATE SERVICE
21/tcp filtered ftp
MAC Address: XX (Tp-link Technologies)
Nmap scan report for 192.168.1.7
Host is up (0.071s latency).
PORT STATE SERVICE
21/tcp closed ftp
MAC Address: ZZ (Unknown)
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.000050s latency).
PORT STATE SERVICE
21/tcp closed ftp
Nmap done: 256 IP addresses (4 hosts up) scanned in 60.62 seconds
快速检测网段中有哪些存活主机(能 ping 通)
root@yalong:~# nmap -n -sP 192.168.1.0/24
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:50 CST
Nmap scan report for 192.168.1.1
Host is up (0.0077s latency).
MAC Address: YY (Huawei Technologies)
Nmap scan report for 192.168.1.2
Host is up (0.0077s latency).
MAC Address: XX (Tp-link Technologies)
Nmap scan report for 192.168.1.7
Host is up (0.0083s latency).
MAC Address: ZZ (Unknown)
Nmap scan report for 192.168.1.6
Host is up.
Nmap done: 256 IP addresses (4 hosts up) scanned in 26.91 seconds
检测IP地址位于192.168.1.5~7 的主机是否开启文件共享
root@yalong-:# nmap -p 139,445 192.168.1.5-7
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:50 CST
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.00014s latency).
PORT STATE SERVICE
139/tcp closed netbios-ssn
445/tcp closed microsoft-ds
Nmap done: 3 IP addresses (1 host up) scanned in 0.77 seconds
下面，nmap工具的基本用法：
扫描特定主机：
root@yalong-:# nmap 192.168.1.6
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:53 CST
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.000018s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 1 IP address (1 host up) scanned in 1.67 seconds
扫描整个子网：
root@yalong-:~# nmap 192.168.1.1/24
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:53 CST
Nmap scan report for _gateway (192.168.1.1)
Host is up (0.0070s latency).
Not shown: 996 closed ports
PORT STATE SERVICE
22/tcp filtered ssh
23/tcp filtered telnet
53/tcp open domain
80/tcp open http
MAC Address: AA (Huawei Technologies)
Nmap scan report for 192.168.1.2
Host is up (0.0067s latency).
All 1000 scanned ports on 192.168.1.2 are filtered
MAC Address: ZZ (Tp-link Technologies)
Nmap scan report for 192.168.1.7
Host is up (0.014s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
62078/tcp open iphone-sync
MAC Address: XX (Unknown)
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.000041s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 256 IP addresses (4 hosts up) scanned in 150.95 seconds
扫描多个目标：
root@yalong-:~# nmap 192.168.1.6 192.168.1.7
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:54 CST
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.000019s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 2 IP addresses (1 host up) scanned in 2.15 seconds
扫描一个范围内主机：
#nmap 192.168.1.1-10 (扫描IP地址为192.168.1.1-192.168.1.10内的所有主机)
root@yalong-:# nmap 192.168.1.1-10
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:54 CST
Nmap scan report for 192.168.1.2
Host is up (0.036s latency).
All 1000 scanned ports on 192.168.1.2 are filtered
MAC Address: ZZ (Tp-link Technologies)
Nmap scan report for peer1 (192.168.1.6)
Host is up (0.000030s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 10 IP addresses (2 hosts up) scanned in 39.80 seconds
向目标发送两个ping数据包：
root@yalong-:# nmap -sn -PE 2 --send-ip 192.168.1.6
Starting Nmap 7.60 ( https://nmap.org ) at 2021-02-10 14:55 CST
Nmap scan report for peer1 (192.168.1.6)
Host is up.
Nmap done: 2 IP addresses (1 host up) scanned in 2.10 seconds