玩玩nmap

[root@miyan ~]# nmap -v

Starting Nmap 7.12 ( https://nmap.org ) at 2016-04-04 15:34 CST
Read data files from: /usr/bin/../share/nmap
WARNING: No targets were specified, so 0 hosts scanned.
Nmap done: 0 IP addresses (0 hosts up) scanned in 0.07 seconds
Raw packets sent: 0 (0B) | Rcvd: 0 (0B)

Usage: nmap [Scan Type(s)] [Options] {target specification}

[root@miyan ~]# nmap -sS 172.18.16.203

Starting Nmap 7.12 ( https://nmap.org ) at 2016-04-04 18:27 CST
Nmap scan report for 172.18.16.203
Host is up (0.0062s latency).
Not shown: 994 filtered ports
PORT      STATE SERVICE
22/tcp    open  ssh
80/tcp    open  http
111/tcp   open  rpcbind
443/tcp   open  https
5120/tcp  open  unknown
50000/tcp open  ibm-db2

Nmap done: 1 IP address (1 host up) scanned in 4.88 seconds

[root@miyan ~]# nmap -sN 172.18.16.203

Starting Nmap 7.12 ( https://nmap.org ) at 2016-04-04 18:30 CST
Nmap scan report for 172.18.16.203
Host is up (0.0013s latency).
All 1000 scanned ports on 172.18.16.203 are open|filtered

Nmap done: 1 IP address (1 host up) scanned in 21.15 seconds

https://linux.cn/article-2561-3.html