nc (netcat) - alex-aleyan/linux_wiki GitHub Wiki

nc (netcat)

References:

• Port Scanning:
  • scan for open ports in the range 20-80
    • netstat -netupa
    • nc -z -v 10.10.8.8 20-80
      • -z: only scan for open ports
      • -v: verbose.
      • -u: udp (otherwise tcp)
    • nc -z -v 10.10.8.8 20-80 2>&1 | grep succeeded
    • for aport in {20..80}; do nc -z -v -u <YOUR IP ADDRESS> $aport 2>&1| grep succeeded
• Sending/Receiving:
  • UDP example:
    • Listener (Server):
      • nc -u -l 127.0.0.1 9999
    • Sender (Client):
      • nc -u 127.0.0.1 9999
  • TCP (2-way so really both are listener) example:
    • Connection Listener (Server):
      • nc -l 127.0.0.1 9999
    • Connection Sender (Client):
      • nc 127.0.0.1 9999