Linux安全之端口扫描（NMAP）

1、安装NMAP工具

yum -y install nmap

2、查看本机本机对外开放的端口

nmap -sT 127.0.0.1

Starting Nmap 6.40 ( http://nmap.org ) at 2020-07-04 15:12 CST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0012s latency).
Not shown: 998 closed ports
PORT   STATE SERVICE
22/tcp open  ssh
25/tcp open  smtp

Nmap done: 1 IP address (1 host up) scanned in 0.13 seconds

从上面可以开出本机对外开放的端口为22、25

下面我们尝试扫描局域网中其他主机开放的端口

3、将主机B的系统核心防护及防火墙关闭

[root@localhost ~]# setenforce 0
[root@localhost ~]# systemctl stop firewalld

4、使用工具扫描主机B

[root@localhost ~]# nmap -sT 192.168.50.131

Starting Nmap 6.40 ( http://nmap.org ) at 2020-07-04 15:19 CST
Nmap scan report for 192.168.50.131
Host is up (0.0017s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
22/tcp open  ssh
MAC Address: 00:0C:29:5B:F2:D9 (VMware)

Nmap done: 1 IP address (1 host up) scanned in 0.38 seconds

就这样主机B对外开放的端口被扫描出来了