Linux之nc命令

Posted 2021-08-25 wx580ec8c84ec69

Centos安装nc

> yum -y install nc

Ubuntu安装nc

> apt-get install netcat

Mac安装nc

> brew install netcat

命令格式

nc [-hlnruz][-g&lt;网关...&gt;][-G&lt;指向器数目&gt;][-i&lt;延迟秒数&gt;][-o&lt;输出文件&gt;][-p&lt;通信端口&gt;]<br/>[-s&lt;来源位址&gt;][-v...][-w&lt;超时秒数&gt;][主机名称][通信端口...]

命令选项

• -g<网关> 设置路由器跃程通信网关，最多可设置8个。
• -G<指向器数目> 设置来源路由指向器，其数值为4的倍数。
• -h 在线帮助。
• -i<延迟秒数> 设置时间间隔，以便传送信息及扫描通信端口。
• -l 使用监听模式，管控传入的资料。
• -n 直接使用IP地址，而不通过域名服务器。
• -o<输出文件> 指定文件名称，把往来传输的数据以16进制字码倾倒成该文件保存。
• -p<通信端口> 设置本地主机使用的通信端口。
• -r 乱数指定本地与远端主机的通信端口。
• -s<来源位址> 设置本地主机送出数据包的IP地址。
• -u 使用UDP传输协议。
• -v 显示指令执行过程。
• -w<超时秒数> 设置等待连线的时间。
• -z 使用0输入/输出模式，只在扫描通信端口时使用。

TCP端口扫描

> nc -v -z  -w2  rumenz.com  20-30
nc: connectx to rumenz.com port 20 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 21 (tcp) failed: Connection refused
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif en0
    src 192.168.0.105 port 57984
    dst 203.195.152.245 port 22
    rank info not available
    TCP aux info available

Connection to rumenz.com port 22 [tcp/ssh] succeeded!
nc: connectx to rumenz.com port 23 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 24 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 25 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 26 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 27 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 28 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 29 (tcp) failed: Connection refused
nc: connectx to rumenz.com port 30 (tcp) failed: Connection refused

UDP端口扫描

> nc -v -z -w2 -u rumenz.com 20-25
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 63603
    dst 203.195.152.245 port 20
    rank info not available

Connection to rumenz.com port 20 [udp/ftp-data] succeeded!
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 51642
    dst 203.195.152.245 port 21
    rank info not available

Connection to rumenz.com port 21 [udp/ftp] succeeded!
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 58180
    dst 203.195.152.245 port 22
    rank info not available

Connection to rumenz.com port 22 [udp/ssh] succeeded!
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 57409
    dst 203.195.152.245 port 23
    rank info not available

Connection to rumenz.com port 23 [udp/telnet] succeeded!
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 59767
    dst 203.195.152.245 port 24
    rank info not available

Connection to rumenz.com port 24 [udp/*] succeeded!
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.168.0.105 port 58696
    dst 203.195.152.245 port 25
    rank info not available

Connection to rumenz.com port 25 [udp/smtp] succeeded!

扫描指定端口

> nc -v json.im 80
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif en0
    src 192.168.0.105 port 58683
    dst 150.109.147.28 port 80
    rank info not available
    TCP aux info available

Connection to json.im port 80 [tcp/http] succeeded!

建立 C/S 聊天室

模拟 Server 端

> nc -v -l 127.0.0.1 8086

> nc -v -p 8085 localhost 8086

发送文件

Server 端接收文件

> nc -l 127.0.0.1 8086 > s.txt

Client 端发送文件：

> nc 127.0.0.1 8086 < c.txt

支持 UDP 和 IPv6 连接

Server 端：

> nc -u -6 -l localhost 8086

Client 端

> nc -u -6 localhost 8086

原文链接:https://rumenz.com/rumenbiji/linux-nc.html
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