本文共 1573 字，大约阅读时间需要 5 分钟。

1. telnet法

TCP端口开了$ echo "" | telnet 123.1.2.3 8100Trying 123.1.2.3...Connected to 123.1.2.3.Escape character is '^]'.Connection closed by foreign host.TCP端口关了$ echo "" | telnet 123.1.2.3 8101Trying 123.1.2.3...telnet: connect to address 123.1.2.3: Connection refused

如果希望带源地址测试，可以

telnet -b source_ip destanation_ip port

2. nc法

TCP端口开了$ nc -nzv 123.1.2.3 7205       Ncat: Version 7.50 ( https://nmap.org/ncat )Ncat: Connected to 123.1.2.3:7205.Ncat: 0 bytes sent, 0 bytes received in 0.03 seconds.TCP端口关了$ nc -nzv 123.1.2.3 7206Ncat: Version 7.50 ( https://nmap.org/ncat )Ncat: Connection timed out.

如果希望带源地址测试，可以

nc -s source_ip -zv destanation_ip port

3. nmap法

TCP端口开了$ nmap -Pn -sT 123.1.2.3 -p 8100Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:12 CSTNmap scan report for nothing.attdns.com (123.1.2.3)Host is up (0.0067s latency).PORT     STATE SERVICE8100/tcp open  xprint-serverNmap done: 1 IP address (1 host up) scanned in 0.07 secondsTCP端口关了$ nmap -Pn -sT 123.1.2.3 -p 8101Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:12 CSTNmap scan report for nothing.attdns.com (123.1.2.3)Host is up.PORT     STATE    SERVICE8101/tcp filtered unknownNmap done: 1 IP address (1 host up) scanned in 2.08 secondsTCP端口开了啥$ nmap -Pn -sT 123.1.2.3 -p 8000-8300Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:11 CSTNmap scan report for nothing.attdns.com (123.1.2.3)Host is up (0.0083s latency).Not shown: 299 filtered portsPORT     STATE SERVICE8081/tcp open  blackice-icecap8100/tcp open  xprint-serverNmap done: 1 IP address (1 host up) scanned in 10.00 seconds

转载地址：http://ssjxz.baihongyu.com/