nc 命令使用詳解

nc 命令介紹：

Ncat is a feature-packed networking utility which reads and writes data across networks from the command line. Ncat was written for the Nmap Project and is the culmination of the currently splintered family of Netcat incarnations. It is designed to be a reliable back-end tool to instantly provide network connectivity to other applications and users. Ncat will not only work with IPv4 and IPv6 but provides the user with a virtually limitless number of potential uses.

我們通過 ll 命令查看nc 命令：

➜  benchmarks ll /usr/bin/nc
lrwxrwxrwx. 1 root root 4 Feb 19 19:09 /usr/bin/nc -> ncat

nc 命令 是 ncat 的軟鏈接。ncat 與 cat 有著相似的作用， 我們從命名就可以看出來：

NAME
       cat - concatenate files and print on the standard output

NAME
       ncat - Concatenate and redirect sockets

nc 常用：

• 偵聽任意埠，以TCP/UDP 方式
• 埠掃描
• 傳輸文件
• 測速

常用命令：

➜  benchmarks nc -l 8888 -v
Ncat: Version 7.60 ( https://nmap.org/ncat )
Ncat: Generating a temporary 1024-bit RSA key. Use --ssl-key and --ssl-cert to use a permanent one.
Ncat: SHA-1 fingerprint: 045B 595F 7C98 9C19 8632 46C4 1952 C3CA 6560 E0E6
Ncat: Listening on :::8888
Ncat: Listening on 0.0.0.0:8888

 連接埠：

➜  benchmarks nc -vz -w 5 127.0.0.1 8888
Ncat: Version 7.60 ( https://nmap.org/ncat )
Ncat: Connected to 127.0.0.1:8888.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.

 如果進行埠掃描： nc -vz -w 5 127.0.0.1 1-100 對 1-100 埠進行掃描

同理，利用兩者之間的連接可以進行文件傳輸。

如果結合 /dev/null 、/dev/zero 和 dstat 命令，可以進行兩主機之間的網速。