命令简介
nmap（Network Mapper - 网络映射器）命令用于网络探测和安全审核，是网络探索工具和端口扫描程序。namp 它可以扫描单主机，也可以快速扫描大型网络结构。
nmap 输出信息是你所扫描目标的列表，且每个目标都有详细的信息展示，具体的展示信息取决于所使用的选项。该信息中的关键是“有趣的端口表”。该表列出了端口号和协议，服务名称以及状态。状态为打开，已过滤，已关闭或未过滤。
[root@CentOS7-1 ~]# nmap --help
-bash: nmap: command not found
[root@CentOS7-1 ~]# yum install nmap -y
语法格式
nmap [Scan Type...] [Options] {target specification}
选项说明
-O #激活探测操作
-P0 #只进行扫描，不ping主机
-PT #是同TCP的ping
-sV #显示服务版本信息
-sP #ping扫描，仅发现目标主机是否存活
-ps #发送同步（SYN）报文
-PU #发送udp ping
-PE #强制执行直接的ICMPping
-PB #默认模式
-6 #使用IPv6地址
-v #详细信息
-d #增加调试信息地输出
-A #使用所有高级扫描选项
--resume #恢复（继续上次）中止的扫描
-P #指定要扫描的端口，可以是一个端口，用逗号隔开多个端口，使用“-”表示端口范围
-e #在多网络接口Linux系统中，指定扫描使用的网络接口
-g #将指定的端口作为源端口进行扫描
--ttl #指定发送的扫描报文的生存期
--packet-trace #显示扫描过程中收发报文统计
--scanflags #设置在扫描报文中的TCP标志
--send-eth/--send-ip #使用原始以太网发送/构造指定IP发送
应用举例
典型的扫描
[root@CentOS7-1 ~]# nmap -A www.baidu.com
Starting Nmap 6.40 ( http://nmap.org ) at 2021-03-13 04:30 EST
Nmap scan report for www.baidu.com (36.152.44.95)
Host is up (0.012s latency).
Other addresses for www.baidu.com (not scanned): 36.152.44.96
Not shown: 998 filtered ports
PORT STATE SERVICE VERSION
80/tcp open http-proxy sslstrip
|_http-methods: No Allow or Public header in OPTIONS response (status code 302)
| http-robots.txt: 10 disallowed entries
| /baidu /s? /ulink? /link? /home/news/data/ /bh /shifen/
|_/homepage/ /cpro /
|_http-title: xE7x99xBExE5xBAxA6xE4xB8x80xE4xB8x8BxEFxBCx8CxE4xBDxA0xE5xB0xB1xE7x9FxA5xE9x81x93
443/tcp open ssl/http-proxy sslstrip
|_http-methods: No Allow or Public header in OPTIONS response (status code 302)
| http-robots.txt: 10 disallowed entries
| /baidu /s? /ulink? /link? /home/news/data/ /bh /shifen/
|_/homepage/ /cpro /
|_http-title: Site doesn't have a title (text/html).
| ssl-cert: Subject: commonName=baidu.com/organizationName=Beijing Baidu Netcom Science Technology Co., Ltd/stateOrProvinceName=beijing/countryName=CN
| Not valid before: 2020-04-02T06:04:58+00:00
|_Not valid after: 2021-07-26T04:31:02+00:00
|_ssl-date: 2021-03-16T03:14:21+00:00; +2d17h43m18s from local time.
| tls-nextprotoneg:
|_ http/1.1
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: specialized|switch
Running (JUST GUESSING): AVtech embedded (88%), HP embedded (86%)
OS CPE: cpe:/h:hp:procurve_switch_4000m
Aggressive OS guesses: AVtech Room Alert 26W environmental monitor (88%), HP 4000M ProCurve switch (J4121A) (86%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 10 hops
TRACEROUTE (using port 80/tcp)
HOP RTT ADDRESS
1 0.97 ms 192.168.1.1
2 4.96 ms 100.106.0.1
3 ... 9
10 15.25 ms 36.152.44.95
OS and Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 37.64 seconds
TCP 端口扫描
[root@CentOS7-1 ~]# nmap -sT 192.168.1.100
Starting Nmap 6.40 ( http://nmap.org ) at 2021-03-13 04:32 EST
Nmap scan report for 192.168.1.100
Host is up (0.00037s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 1 IP address (1 host up) scanned in 0.07 seconds
扫描1-65535
[root@CentOS7-1 ~]# nmap -p 1-65535 -T4 -A -v 192.168.1.100
Starting Nmap 6.40 ( http://nmap.org ) at 2021-03-13 04:33 EST
NSE: Loaded 110 scripts for scanning.
NSE: Script Pre-scanning.
Initiating Parallel DNS resolution of 1 host. at 04:33
Completed Parallel DNS resolution of 1 host. at 04:33, 0.00s elapsed
Initiating SYN Stealth Scan at 04:33
Scanning 192.168.1.100 [65535 ports]
Discovered open port 22/tcp on 192.168.1.100
Discovered open port 19999/tcp on 192.168.1.100
Completed SYN Stealth Scan at 04:33, 6.82s elapsed (65535 total ports)
Initiating Service scan at 04:33
Scanning 2 services on 192.168.1.100
Completed Service scan at 04:33, 19.10s elapsed (2 services on 1 host)
Initiating OS detection (try #1) against 192.168.1.100
NSE: Script scanning 192.168.1.100.
Initiating NSE at 04:34
Completed NSE at 04:34, 0.14s elapsed
Nmap scan report for 192.168.1.100
Host is up (0.000032s latency).
Not shown: 65533 closed ports
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.4 (protocol 2.0)
| ssh-hostkey: 2048 37:71:8e:4a:db:cc:ac:29:f2:a2:20:93:23:8c:f6:e8 (RSA)
|_256 cc:4b:7d:b6:59:0f:77:83:a9:a5:32:70:4e:87:0d:41 (ECDSA)
19999/tcp open unknown
1 service unrecognized despite returning data. If you know the service/version, please submit the following fingerprint at http://www.insecure.org/cgi-bin/servicefp-submit.cgi :
SF-Port19999-TCP:V=6.40%I=7%D=3/13%Time=604C86FA%P=x86_64-redhat-linux-gnu
SF:%r(GenericLines,190,"HTTP/1.1x20400x20Badx20RequestrnConnection:
SF:x20closernServer:x20NetDatax20Embeddedx20HTTPx20Serverx20v1.29
SF:.3rnAccess-Control-Allow-Origin:x20*rnAccess-Control-Allow-Creden
SF:tials:x20truernContent-Type:x20text/plain;x20charset=utf-8rnDate
SF::x20Sat,x2013x20Marx202021x2009:33:46x20GMTrnCache-Control:x20
SF:no-cache,x20no-store,x20must-revalidaternPragma:x20no-cachernExp
SF:ires:x20Sat,x2013x20Marx202021x2009:33:47x20GMTrnContent-Length
SF::x2027rnrnIx20don'tx20understandx20you...rn")%r(GetRequest
SF:,5580,"HTTP/1.1x20200x20OKrnConnection:x20closernServer:x20Net
SF:Datax20Embeddedx20HTTPx20Serverx20v1.29.3rnAccess-Control-Allow
SF:-Origin:x20*rnAccess-Control-Allow-Credentials:x20truernContent-
SF:Type:x20text/html;x20charset=utf-8rnDate:x20Tue,x2009x20Febx202
SF:021x2010:11:54x20GMTrnCache-Control:x20publicrnExpires:x20Sun,
SF:x2014x20Marx202021x2009:33:46x20GMTrnContent-Length:x2085228rn
SF:rnnetdatax20dash
SF:board
SF: UDP 端口扫描
[root@CentOS7-1 ~]# nmap -sU 192.168.1.100
Starting Nmap 6.40 ( http://nmap.org ) at 2021-03-13 04:34 EST
Nmap scan report for 192.168.1.100
Host is up (0.0000040s latency).
All 1000 scanned ports on 192.168.1.100 are closed
Nmap done: 1 IP address (1 host up) scanned in 1.65 seconds