How to use Linux nc commands

Run this command to set vro parameters.

Syntax

Nc [-hlnruz] [-g <gateway...>] [-G <number of pointers>] [-I <delay in seconds>] [-o <output file>] [-p <communication Port>]

[-S <source address>] [-v...] [-w <timeout seconds>] [host name] [communication port...]

Parameter description:

• -G <Gateway> sets up eight router hop communication gateways.
• -G <number of pointers> sets the source route indicator, which is a multiple of 4.
• -H online help.
• -I <latency in seconds> set the interval to send information and scan the communication port.
• -L use the listener mode to control incoming data.
• -N directly uses the IP address instead of the domain name server.
• -O <output file> specifies the file name, dumping the data that is being transferred in hexadecimal format into this file for storage.
• -P <communication Port> sets the communication port used by the local host.
• -R: specifies the communication port between the local host and the remote host.
• -S <source address> sets the IP address of the data packet sent from the local host.
• -U uses UDP transmission protocol.
• -V shows the command execution process.
• -W <timeout seconds> sets the waiting time.
• -Z uses the 0 input/output mode and is only used when scanning communication ports.

Instance

TCP port scan

# Nc-v-z-w2 192.168.0.3 1-100

192.168.0.3: inverse host lookup failed: Unknown host

(UNKNOWN) [192.168.0.3] 80 (http) open

(UNKNOWN) [192.168.0.3] 23 (telnet) open

(UNKNOWN) [192.168.0.3] 22 (ssh) open

The port range for scanning 192.168.0.3 is 1-100.

Scan UDP port

# Nc-u-z-w2 192.168.0.1 1-1000 // scan port range of 192.168.0.3 is 1-1000

Scan specified port

# Nc-nvv 192.168.0.1 80 // scan port 80

(UNKNOWN) [192.168.0.1] 80 (?) Open

Y // user input