root@10.1.1.43:~# nc -h
[v1.10-38]
connect to somewhere: nc [-options] hostname port[s] [ports] ...
listen for inbound: nc -l -p port [-options] [hostname] [port]
options:
-c shell commands as `-e'; use /bin/sh to exec [dangerous!!]
-e filename program to exec after connect [dangerous!!]
-b allow broadcasts
-g gateway source-routing hop point[s], up to 8 设置路由器跃程通信网关，最高可设置8个。
-G num source-routing pointer: 4, 8, 12, ... 设置来源路由指向器，其数值为4的倍数。
-h this cruft
-i secs delay interval for lines sent, ports sca 延时的间隔
-k set keepalive option on socket
-l listen mode, for inbound connects 监听模式,入站连接
-n numeric-only IP addresses, no DNS 直接使用ip地址,而不用域名服务器
-o file hex dump of traffic 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 port local port number 本地端口
-r randomize local and remote ports 随机本地和远程端口
-q secs quit after EOF on stdin and delay of secs
-s addr local source address
-T tos set Type Of Service
-t answer TELNET negotiation
-u UDP mode udp 模式
-v verbose [use twice to be more verbose] 显示过程,vv 更多
-w secs timeout for connects and final net reads 等待连接超时
-z zero-I/O mode [used for scanning] 使用输入/输出模式，只在扫描通信端口时使用。
1.监听本地端口
root@10.1.1.43:~# nc -l -p 1234
root@10.1.1.43:~# netstat -tunlp | grep 1234
tcp 0 0 0.0.0.0:1234 0.0.0.0:* LISTEN 15543/nc
2.端口扫描
root@10.1.1.43:~# nc -v -w 10 10.1.1.180 80
(UNKNOWN) [10.1.1.180] 80 (www) open
root@10.1.1.43:~# nc -v -w 10 10.1.1.180 -z 80-30000
(UNKNOWN) [10.1.1.180] 22000 (?) open
(UNKNOWN) [10.1.1.180] 80 (www) open
3.文件传出
源10.1.1.43 text.txt
目的 10.1.1.180
root@10:~# nc -l -p 1234 > test.txt #开10.1.1.180:1234端口监听，并将socket传输过来的数据重定向到test.txt文件 test 43 nc
root@10.1.1.43:~#cat test.txt
root@10.1.1.43:~# nc 10.1.1.180 1234 < test.txt #连接远程的10.1.1.180，从test.txt的路径从定向到socket，从而将文件传输到远方。
root@10:~# cat test.txt
4.目录传输
源10.1.1.43 python_program
目的 10.1.1.180
root@10:~# nc -l -p 1234 | tar xzvf -
root@10.1.1.43:~# tar czvf - python_program | nc 10.1.1.180 1234
python_program/
python_program/1.py
python_program/4.py
python_program/3.py
5.测试UDP端口
root@172.16.211.34:web# netstat -tunlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1111/sshd
udp 0 0 0.0.0.0:68 0.0.0.0:* 887/dhclient
root@172.16.211.35:~# nc -vuz 172.16.211.34 68
Connection to 172.16.211.34 68 port [udp/bootpc] succeeded!