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
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[root@localhost ~] # telnet 10.0.250.3 80
Trying 10.0.250.3...
telnet: connect to address 10.0.250.3: Connection refused #直接提示连接被拒绝
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2)再连接存在的端口
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[root@localhost ~] # telnet localhost 22
Trying ::1...
Connected to localhost. #看到Connected就连接成功了
Escape character is '^]' .
SSH-2.0-OpenSSH_5.3
a
Protocol mismatch.
Connection closed by foreign host.
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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
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[root@localhost ~] # ssh 10.0.250.3 -p 80
ssh : connect to host 10.0.250.3 port 80: Connection refused
[root@localhost ~] # ssh 10.0.250.3 -p 80 -v
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: 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 refused
ssh : connect to host 10.0.250.3 port 80: Connection refused
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2)连接存在的端口
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[root@localhost ~] # ssh ... -p
a
^]
^C
[root@localhost ~] # ssh ... -p -v
OpenSSH_.p, OpenSSL ..e-fips Feb
debug: Reading configuration data /etc/ssh/ssh_config
debug: 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
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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
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[root@localhost ~] # wget ...:
---- ::-- http: // .../
Connecting to ...:... failed: Connection refused.
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2)连接存在的端口
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[root@localhost ~] # wget ...:
---- ::-- http: // ...:/
Connecting to ...:... connected.
HTTP request sent, awaiting response...
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4、使用端口扫描工具
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[root@localhost ~] # nmap ... -p
Starting Nmap . ( http: //nmap .org ) at -- : CST
Nmap scan report for ...
Host is up (.s latency).
PORT STATE SERVICE
/tcp closed http
MAC 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 -- : CST
Nmap scan report for ...
Host is up (.s latency).
PORT STATE SERVICE
/tcp open http-proxy
MAC 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 -- : CST
Nmap scan report for ...
Host is up (.s latency).
Not shown: closed ports
PORT STATE SERVICE
/tcp open ssh
/tcp open rpcbind
/tcp open http-proxy
/tcp open unknown
MAC Address: B:A::CF:FD:D (Unknown)
Nmap done : IP address ( host up) scanned in . seconds
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curl法
curl是利用URL语法在命令行方式下工作的开源文件传输工具。也可以用来测试端口的连通性,具体用法:
curl ip:port
说明:
ip:是测试主机的ip地址
port:是端口,比如80
如果远程主机开通了相应的端口,都会输出信息,如果没有开通相应的端口,则没有任何提示,需要CTRL+C断开。
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.
摘自网络