NC basic usage 1

Port scanning

[[email protected] ~]# nc -zvn 192.168.100.101  20-25
nc: connect to 192.168.100.101 port 20 (tcp) failed: No route to host
nc: connect to 192.168.100.101 port 21 (tcp) failed: No route to host
Connection to 192.168.100.101 22 port [tcp/*] succeeded!
nc: connect to 192.168.100.101 port 23 (tcp) failed: No route to host
nc: connect to 192.168.100.101 port 24 (tcp) failed: No route to host
nc: connect to 192.168.100.101 port 25 (tcp) failed: No route to host
[[email protected] ~]# nc -zvn 192.168.100.101  3306
Connection to 192.168.100.101 3306 port [tcp/*] succeeded!
[[email protected] ~]# 

Open a session connection

[[email protected] ~]# nc -l 12345
hello
for test
i miss you
^_^
----------
[[email protected] BGPtest]# nc h102 12345
hello  
for test
i miss you
^_^ 

At the moment , To confirm server The firewall at the end is for 12345 The port is open

File transfer

server End send file

[[email protected] nc]# echo "abc test" > file.txt
[[email protected] nc]# nc -l 2345 < file.txt 
----------
[[email protected] nc]# nc h102 2345 > f.txt
[[email protected] nc]# cat f.txt 
abc test
[[email protected] nc]# 

server Receiving documents

[[email protected] nc]# nc -l 2345 > file.txt 
----------
[[email protected] nc]# echo "uiuiuiuiui" > f.txt 
[[email protected] nc]# nc -v h102 2345 < f.txt
Connection to h102 2345 port [tcp/dbm] succeeded!
[[email protected] nc]# 
----------
[[email protected] nc]# cat file.txt 
uiuiuiuiui
[[email protected] nc]#