-P0：跳过 ping 检测：这种方式认为所有的目标主机是存活的，当对方不响应 ICMP请求时，使用这种方式可以避免因无法 ping 通而放弃扫描。
[root@localhost run]# nmap -sT 127.0.0.1 //检测本地开放的TCP端口 Starting Nmap 6.40 ( ) at 2019-09-02 03:19 CST Nmap scan report for localhost (127.0.0.1) Host is up (0.00082s latency). Not shown: 996 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 111/tcp open rpcbind 631/tcp open ipp Nmap done: 1 IP address (1 host up) scanned in 0.06 seconds [root@localhost run]# nmap -sU 127.0.0.1 //检测本地开放的TCP端口 Starting Nmap 6.40 ( ) at 2019-09-02 03:21 CST Nmap scan report for localhost (127.0.0.1) Host is up (0.000049s latency). Not shown: 997 closed ports PORT STATE SERVICE 68/udp open|filtered dhcpc 111/udp open rpcbind 5353/udp open|filtered zeroconf Nmap done: 1 IP address (1 host up) scanned in 48.95 seconds [root@localhost run]# nmap -sP 192.168.31.12 //检测地址主机是否存活 Starting Nmap 6.40 ( ) at 2019-09-02 03:24 CST Nmap scan report for 192.168.31.12 Host is up (0.00067s latency). Nmap done: 1 IP address (1 host up) scanned in 0.17 seconds [root@localhost run]# nmap -sT 192.168.31.12 //检测目标地址主机开放的TCP端口 Starting Nmap 6.40 ( ) at 2019-09-02 03:30 CST Nmap scan report for 192.168.31.12 Host is up (0.0019s latency). Not shown: 995 filtered ports PORT STATE SERVICE 135/tcp open msrpc 139/tcp open netbios-ssn 443/tcp open https 445/tcp open microsoft-ds 902/tcp open iss-realsecure Nmap done: 1 IP address (1 host up) scanned in 9.32 seconds谢谢阅读。