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redes:notas:nc

Netcat

Netcat is a featured networking utility which reads and writes data across network connections, using the TCP/IP protocol. It is designed to be a reliable “back-end” tool that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and exploration tool, since it can create almost any kind of connection you would need and has several interesting built-in capabilities.

It provides access to the following main features:

  • Outbound and inbound connections, TCP or UDP, to or from any ports.
  • Featured tunneling mode which allows also special tunneling such as UDP to TCP, with the possibility of specifying all network parameters (source port/interface, listening port/interface, and the remote host allowed to connect to the tunnel.
  • Built-in port-scanning capabilities, with randomizer.
  • Advanced usage options, such as buffered send-mode (one line every N seconds), and hexdump (to stderr or to a specified file) of trasmitted and received data.
  • Optional RFC854 telnet codes parser and responder.

The GNU Netcat is distributed freely under the GNU General Public License (GPL).

Ejemplos de uso

GET HTTP

echo  -e "GET / HTTP/1.0\r\n" | nc 192.168.1.1 80

Pasar un archivo de un equipo a otros

Desde el servidor

cat backup.iso | nc -l 3333

Desde el cliente

nc 192.168.0.1 3333 > backup.iso

Si queremos poner un contador

nc 192.168.0.1 3333 | pv -b > backup.iso

Otro ejemplo

Desde el servidor

dd if=/dev/hdb5 | gzip -9 | nc -l 3333

Desde el cliente

nc 192.168.0.1 3333 | pv -b > myhdb5partition.img.gz

Consultando puertos abiertos

for port in {1..65535}; do
  nc -w 1 localhost $port > /dev/null && echo "Port $port open" || echo "Port $port closed";
done

Fuente : http://adamish.com/blog/archives/567

Referencias

redes/notas/nc.txt · Última modificación: 2018/11/01 16:35 por cayu