Netcat

Netcat is the swiss army knife of the hackers. Netcat is used for file (exploit) transfer, finding open ports & remote administration (Bind & Reverse Shells). You can manually connect to any network service like HTTP using netcat. Another utility is to listen on any UDP/TCP ports on your machine for any incoming connections.

• Windows: ncat.exe
• Linux:
  • nc (netcat-openbsd package)
  • ncat (nmap package)

nc examples

• echo "text to send" | nc IP port
• echo "text to send" | nc 10.10.10.10 54

• Forward port (see also socat):

nc -l -p ORIGIN_PORT -c 'nc DESTINATION_IP DESTINATIO_PORT'

nc -l -p 2222 -c 'nc 10.10.10.4 8888'

nc <IPaddress or FQDN> <port number>

nc -vnzu  5x.253.51.xxx 4501
Connection to 5x.253.51.xxx 4501 port [udp/*] succeeded!
-u Use UDP
-v verbose
-z  specifies that nc should just scan for listening daemons, without sending any data to them

nc -zv google.com 80
Connection to google.com 80 port [tcp/http] succeeded!

nc -zv google.com 443
Connection to google.com 443 port [tcp/https] succeeded!

UDP (-u)
nc -u XXXXX

Related commands

• iperf
• pv </dev/zero | ssh REMOTE_SERVER 'cat >/dev/null'
• nping
• netstat

See also

• OpenSSH (changelog): /etc/ssh/sshd_config | /etc/ssh/ssh_config | ~/.ssh/ | openSSL | sshd logs | sftp | scp | authorized_keys | ssh-keygen | ssh-keyscan | ssh-add | ssh-agent | ssh | Ssh -O stop | ssh-copy-id | CheckHostIP | UseKeychain, OpenSSF
• telnet, netcat, nc, nc -l, ncat, socat, ngrok
• Security tools: Vulnerability scanner, port scan, Host sweep, nmap, nping, ncat, nc, psad, Gordon Lyon