nc, the full name is netcat, it can be used to complete many network functions, such as port scanning, establishing TCP/UDP connections, data transmission, network debugging, etc. Therefore, it is often called the Swiss Army Knife of network tools.
1. Only the server uses nc
Remarks: This method can only send data once, and cannot send data to each other
1. udp sends and receives data, udp does not distinguish between client and server in essence
client
echo 111 > /dev/udp/192.168.43.102/1234
Server
nc -u -l 192.168.43.102 1234 #-u代表使用udp 协议 ip为服务器的ip -l 表示监听这个ip端口；
nc -u -l 1234 #ip也可以不写
2. When tcp sends and receives data, you must first open the nc of the server
client
echo 111 > /dev/tcp/192.168.43.102/1234
Server
nc -l 192.168.43.102 1234 # nc默认使用tcp协议
或
nc -l 1234
2. Use nc at both ends
Remarks: This method can send data to each other multiple times
1、udp
client
nc -u 192.168.43.102 1234
Server
nc -u -l 1234
2、tcp
client
nc 192.168.43.102 1234
Server
nc -l 1234
More detailed reference:
nc network command, establish a connection between two hosts through TCP and UDP to transfer messages and files