TD Cyber Labs

TrainersTool Trainers / Netcat Trainer 0 / 40 pts

Netcat

Red Team · Easy · 4 lessons

Netcat (nc) reads and writes raw TCP connections. Pointed at a port, it prints whatever the service says back — a fast way to fingerprint software and confirm a port is really open. It is also how you catch reverse shells. Practise banner grabbing against 10.10.10.10.

1
Grab a service banner
The simplest use: 'nc host port'. On connect, many services announce themselves — SSH sends its version string straight away. This confirms both that the port is open and what is behind it.
nc 10.10.10.10 22
2
Confirm the connection with -v
-v makes Netcat tell you whether the TCP handshake actually succeeded, printing 'succeeded!' before any banner. Here FTP greets you with its version on port 21.
nc -v 10.10.10.10 21
3
Talk to a web port
HTTP does not speak first — connect to port 80 and it waits for a request. Netcat lets you type one by hand (e.g. 'GET / HTTP/1.0'). Recognising a silent port is itself a clue about the protocol.
nc 10.10.10.10 80
4
Recognise a closed port
Point Netcat at a port nothing is listening on and the connection is refused. Learning to read 'Connection refused' vs a banner is how you separate open ports from closed ones by hand.
nc -v 10.10.10.10 3306

Applications

practice 10.10.10.10--:--

learner@kali: ~ — Terminal