Centos下安装nc命令工具安装以及使用

Posted 2020-12-25 bigdata-stone

　　1)netcat(nc)是一个简单而有用的工具，被誉为网络安全界的“瑞士军刀”，不仅可以通过使用TCP或UDP协议的网络连接读写数据，同时还是一个功能强大的网络调试和探测工具，能够建立你需要的几乎所有类型的网络连接。

　　2)在Linux终端窗口可以直接使用yum工具进行安装：

[[email protected] spark]# yum install nc.x86_64

　　3)安装完毕后，在终端模式下运行nc -help查看命令是否正常安装

[[email protected] spark]$ nc -help
usage: nc [-46DdhklnrStUuvzC] [-i interval] [-p source_port]
          [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_version]
          [-x proxy_address[:port]] [hostname] [port[s]]
        Command Summary:
                -4              Use IPv4
                -6              Use IPv6
                -D              Enable the debug socket option
                -d              Detach from stdin
                -h              This help text
                -i secs         Delay interval for lines sent, ports scanned
                -k              Keep inbound sockets open for multiple connects
                -l              Listen mode, for inbound connects
                -n              Suppress name/port resolutions
                -p port         Specify local port for remote connects
                -r              Randomize remote ports
                -S              Enable the TCP MD5 signature option
                -s addr         Local source address
                -T ToS          Set IP Type of Service
                -C              Send CRLF as line-ending
                -t              Answer TELNET negotiation
                -U              Use UNIX domain socket
                -u              UDP mode
                -v              Verbose
                -w secs         Timeout for connects and final net reads
                -X proto        Proxy protocol: "4", "5" (SOCKS) or "connect"
                -x addr[:port]  Specify proxy address and port
                -z              Zero-I/O mode [used for scanning]
        Port numbers can be individual or ranges: lo-hi [inclusive]

　　OK，安装正常。下面我们就可以使用nc -l 9999 来监听端口，并发送数据；

[[email protected] spark]$ nc -lk 8888
Hello world!
How are you?
Goodbye!

　　在我的CentOS 6.4(64-bit) 环境中执行 nc -l 9999 监听命令遇到protocol not available。

[[email protected] spark]$ nc -l 9999
nc: Protocol not available

解决方法如下：

# Removes the old package
yum erase nc

# Manually downloads the working package from the Official Repository
wget http://vault.centos.org/6.6/os/x86_64/Packages/nc-1.84-22.el6.x86_64.rpm

# Installs the package
rpm -iUv nc-1.84-22.el6.x86_64.rpm

另：本系统为64位操作系统，若读者使用的是i386 (32-bit)，可以使用如下链接：

wget http://vault.centos.org/6.6/os/i386/Packages/nc-1.84-22.el6.i686.rpm