Bash Port Scanner

A fast, feature-rich port scanner written in Bash that uses netcat for reliable TCP port scanning.

✨ Features

• Fast scanning with configurable concurrency
• Flexible port specification (single ports, comma-separated lists, ranges)
• Hostname support (not just IP addresses)
• Colored output for better readability
• Configurable timeout for different network conditions
• Verbose mode for detailed scanning information
• Input validation with helpful error messages
• Progress tracking during scans

🚀 Installation

Prerequisites

• Bash (version 4.0 or higher)
• Netcat (nc) - for TCP port scanning
• Linux/macOS (tested on Ubuntu, CentOS, macOS)

Quick Start

1. Clone the repository:

   git clone https://github.com/jason-allen-oneal/bash-port-scan.git
   cd bash-port-scan

2. Make the script executable:

   chmod +x bash-port-scan.sh

3. Test the installation:

   ./bash-port-scan.sh -h

📖 Usage

Basic Syntax

./bash-port-scan.sh -i <TARGET> -p <PORTS> [OPTIONS]

Required Parameters

• -i, --ip <TARGET>: Target IP address or hostname to scan
• -p, --ports <PORTS>: Port(s) to scan (see Port Formats below)

Optional Parameters

• -v, --verbose: Enable verbose output (show closed ports)
• -t, --timeout <SECONDS>: Connection timeout in seconds (default: 5)
• -c, --concurrent <NUMBER>: Number of concurrent connections (default: 10)
• -h, --help: Show help message

Port Formats

Format	Example	Description
Single port	80	Scan one specific port
Multiple ports	80,443,8080	Scan multiple specific ports
Port range	1-1000	Scan a range of ports
Mixed	22,80,443,8080-8090	Combine single ports and ranges

🔍 Examples

Basic Usage

# Scan common web ports
./bash-port-scan.sh -i 127.0.0.1 -p 80,443

# Scan a port range
./bash-port-scan.sh -i 192.168.1.1 -p 1-1000

# Scan using hostname
./bash-port-scan.sh -i example.com -p 22,80,443

Advanced Usage

# Verbose scan with progress tracking
./bash-port-scan.sh -i 10.0.0.1 -p 22,80,443,8080-8090 -v

# Fast scan with custom timeout and concurrency
./bash-port-scan.sh -i 192.168.1.100 -p 1-65535 -t 3 -c 20

# Quick scan of common ports
./bash-port-scan.sh -i localhost -p 21,22,23,25,53,80,110,143,443,993,995

Network Security Testing

# Scan for common services
./bash-port-scan.sh -i target.example.com -p 21,22,23,25,53,80,110,143,443,993,995,1433,1521,3306,3389,5432,5900,6379,8080,8443

# Quick vulnerability assessment
./bash-port-scan.sh -i 192.168.1.0/24 -p 22,80,443 -t 2 -c 50

📊 Output Examples

Standard Output

Starting port scan...
Target: 127.0.0.1
Ports: 3 (80 443 8080)
Timeout: 5s
Concurrent: 10
----------------------------------------
[OPEN] Port 80
[OPEN] Port 443
----------------------------------------
Scan complete!
Found 2 open port(s) out of 3 scanned

Verbose Output

Starting port scan...
Target: example.com
Ports: 5 (22 80 443 8080 8443)
Timeout: 5s
Concurrent: 10
----------------------------------------
Scanning port 22 (1/5)... [CLOSED] Port 22
Scanning port 80 (2/5)... [OPEN] Port 80
Scanning port 443 (3/5)... [OPEN] Port 443
Scanning port 8080 (4/5)... [CLOSED] Port 8080
Scanning port 8443 (5/5)... [CLOSED] Port 8443
----------------------------------------
Scan complete!
Found 2 open port(s) out of 5 scanned

⚙️ Configuration

Performance Tuning

• Timeout: Lower values (1-3s) for fast local networks, higher values (5-10s) for slower networks
• Concurrency: Higher values (20-50) for faster scanning, lower values (5-10) for stealth scanning
• Port ranges: Use specific port lists instead of large ranges for faster results

Common Use Cases

Scenario	Recommended Settings
Local network scan	-t 2 -c 20
Internet scan	-t 5 -c 10
Stealth scan	-t 3 -c 5
Fast scan	-t 1 -c 50

🔧 Troubleshooting

Common Issues

"Netcat (nc) is required"

# Ubuntu/Debian
sudo apt-get install netcat

# CentOS/RHEL
sudo yum install nc

# macOS
brew install netcat

"Permission denied"

chmod +x bash-port-scan.sh

"Invalid IP address"

• Ensure the target is a valid IP address or hostname
• Check DNS resolution for hostnames

"No open ports found"

• Verify the target is reachable (ping <target>)
• Check firewall settings
• Try increasing timeout with -t 10

📝 License

This project is licensed under the MIT License. See the LICENSE file for details.

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

⚠️ Disclaimer

This tool is for educational and authorized security testing purposes only. Always ensure you have permission to scan the target systems. The authors are not responsible for any misuse of this tool.

📈 Version History

• v0.2 - Enhanced error handling, colored output, new features
• v0.1 - Initial release with basic port scanning functionality