一般情况下使用"telnet ip port"判断端口通不通，其实测试方法不止这一种，还有很多种方法，下面小编给大家分享了几种方法，具体内容请往下看：

准备环境

启动一个web服务器，提供端口.

[wyq@localhost ~]$ python -m SimpleHTTPServer 8080Serving HTTP on 0.0.0.0 port 8080 ...

用其它web服务器提供端口也一样，由于python比较方便，这里就用它

1、使用telnet判断

telnet是windows标准服务，可以直接用；如果是linux机器，需要安装telnet.

用法: telnet ip port

1）先用telnet连接不存在的端口

[root@localhost ~]# telnet 10.0.250.3 80Trying 10.0.250.3...telnet: connect to address 10.0.250.3: Connection refused #直接提示连接被拒绝

2）再连接存在的端口

[root@localhost ~]# telnet localhost 22Trying ::1...Connected to localhost. #看到Connected就连接成功了Escape character is '^]'.SSH-2.0-OpenSSH_5.3aProtocol mismatch.Connection closed by foreign host.

2、使用ssh判断

ssh是linux的标准配置并且最常用，可以用来判断端口吗？

用法: ssh -v -p port username@ip

-v 调试模式(会打印日志).

-p 指定端口

username可以随意

1）连接不存在端口

[root@localhost ~]# ssh 10.0.250.3 -p 80ssh: connect to host 10.0.250.3 port 80: Connection refused[root@localhost ~]# ssh 10.0.250.3 -p 80 -vOpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013debug1: Reading configuration data /etc/ssh/ssh_configdebug1: Applying options for *debug1: Connecting to 10.0.250.3 [10.0.250.3] port 80.debug1: connect to address 10.0.250.3 port 80: Connection refusedssh: connect to host 10.0.250.3 port 80: Connection refused

2）连接存在的端口

[root@localhost ~]# ssh ... -p a^]^C[root@localhost ~]# ssh ... -p -vOpenSSH_.p, OpenSSL ..e-fips Feb debug: Reading configuration data /etc/ssh/ssh_configdebug: Applying options for *debug: Connecting to ... [...] port .debug: Connection established.debug: permanently_set_uid: /debug: identity file /root/.ssh/identity type -debug: identity file /root/.ssh/identity-cert type -debug: identity file /root/.ssh/id_rsa type -debug: identity file /root/.ssh/id_rsa-cert type -debug: identity file /root/.ssh/id_dsa type -debug: identity file /root/.ssh/id_dsa-cert type -a^C

不用-v选项也可以咯

3、使用wget判断

wget是linux下的下载工具，需要先安装.

用法: wget ip:port

1）连接不存在的端口

[root@localhost ~]# wget ...:---- ::-- http://.../Connecting to ...:... failed: Connection refused.

2）连接存在的端口

[root@localhost ~]# wget ...:---- ::-- http://...:/Connecting to ...:... connected.HTTP request sent, awaiting response...

4、使用端口扫描工具

[root@localhost ~]# nmap ... -p Starting Nmap . ( http://nmap.org ) at -- : CSTNmap scan report for ...Host is up (.s latency).PORT STATE SERVICE/tcp closed httpMAC Address: B:A::CF:FD:D (Unknown)Nmap done: IP address ( host up) scanned in . seconds[root@localhost ~]# nmap ... -p Starting Nmap . ( http://nmap.org ) at -- : CSTNmap scan report for ...Host is up (.s latency).PORT STATE SERVICE/tcp open http-proxyMAC Address: B:A::CF:FD:D (Unknown)Nmap done: IP address ( host up) scanned in . seconds[root@localhost ~]# nmap ...Starting Nmap . ( http://nmap.org ) at -- : CSTNmap scan report for ...Host is up (.s latency).Not shown: closed portsPORT STATE SERVICE/tcp open ssh/tcp open rpcbind/tcp open http-proxy/tcp open unknownMAC Address: B:A::CF:FD:D (Unknown)Nmap done: IP address ( host up) scanned in . seconds

总结

提供端口服务，则使用了tcp协议，上面是以web服务器为例。如果服务器是更简单的tcp服务器，三个工具同样适用.

三个工具的共同点是：1.以tcp协议为基础；2.能访问指定端口. 遵循这两点可以找到很多工具.

一般在windows下使用telnet比较方便，linux下个人就比较喜欢用wget.