- telnet法
TCP端口开了
$ echo "" | telnet 123.1.2.3 8100
Trying 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 8101
Trying 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
- 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 7206
Ncat: Version 7.50 ( https://nmap.org/ncat )
如果希望带源地址测试，可以
nc -s source_ip -zv destanation_ip port
- nmap法
TCP端口开了
$ nmap -Pn -sT 123.1.2.3 -p 8100
Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:12 CST
Nmap scan report for nothing.attdns.com (123.1.2.3)
Host is up (0.0067s latency).
PORT STATE SERVICE
8100/tcp open xprint-server
Nmap done: 1 IP address (1 host up) scanned in 0.07 seconds
TCP端口关了
$ nmap -Pn -sT 123.1.2.3 -p 8101
Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:12 CST
Nmap scan report for nothing.attdns.com (123.1.2.3)
Host is up.
PORT STATE SERVICE
8101/tcp filtered unknown
Nmap done: 1 IP address (1 host up) scanned in 2.08 seconds
TCP端口开了啥
$ nmap -Pn -sT 123.1.2.3 -p 8000-8300
Starting Nmap 6.40 ( http://nmap.org ) at 2019-09-29 12:11 CST
Nmap scan report for nothing.attdns.com (123.1.2.3)
Host is up (0.0083s latency).
Not shown: 299 filtered ports
PORT STATE SERVICE
8081/tcp open blackice-icecap
8100/tcp open xprint-server
Nmap done: 1 IP address (1 host up) scanned in
