lhssh - Local Host SSH Scanner and Connection Manager

A modern, dependency-free bash utility for scanning and managing SSH connections to hosts on local networks.

Features

• Fast Network Scanning: Automatically discover SSH-enabled hosts on your local network
• Parallel Scanning: Scan multiple hosts simultaneously for faster results
• Flexible Connection: Connect using full IPs or short notation (e.g., lhssh 152)
• Command Execution: Run commands on remote hosts directly
• Colored Output: Easy-to-read results with optional color coding
• Configurable: Customize scan ranges, timeouts, and display preferences
• No External Dependencies: Pure bash implementation (beyond standard SSH tools)

Requirements

• Bash 5.0 or later
• SSH client (OpenSSH)
• Either ssh-keyscan OR nc (netcat) for network scanning
• timeout command (part of GNU coreutils)
• Standard Unix tools: sed, grep, cut, sort, xargs

Installation

Manual Installation

1. Clone or download the repository:

git clone https://github.com/Open-Technology-Foundation/lhssh.git
cd lhssh

2. Make the scripts executable:

chmod +x lhssh lhssh-cmd

3. Create symlinks in your PATH:

sudo ln -s $(pwd)/lhssh /usr/local/bin/lhssh
sudo ln -s $(pwd)/lhssh-cmd /usr/local/bin/lhssh-cmd

Alternative Installation

Copy the scripts to a directory in your PATH:

sudo cp lhssh lhssh-cmd /usr/local/bin/
sudo chmod +x /usr/local/bin/lhssh /usr/local/bin/lhssh-cmd

Quick Start

1. Scan your network for SSH hosts:

lhssh

2. Connect to a host using short notation:

lhssh 152  # Connects to 192.168.1.152

3. Run a command on a remote host:

lhssh 152 uptime

4. Show only IP addresses:

lhssh -s  # Show full IPs
lhssh -p  # Show last octet only

Usage

lhssh [OPTIONS] [IP [COMMAND...]]

Options

Display Options

• -s, --short - Show IP addresses only (no hostnames)
• -p, --supershort - Show only last octet of IP addresses
• -C, --no-color - Disable colored output
• -v, --verbose - Enable verbose output (use -vv for debug)
• -q, --quiet - Disable all non-essential output

Network Options

• -n, --network PREFIX - Set network prefix (default: 192.168.1.)
• -b, --begin IP - Start IP for scanning (default: 50)
• -f, --finish IP - End IP for scanning (default: 230)

SSH Options

• -u, --user USERNAME - SSH username (default: current user)
• -t, --timeout SECS - Connection timeout (default: 10)
• -T, --session-time SECS - Session timeout (default: 600)

Configuration

• -l, --list - Show current configuration
• -e, --edit - Edit configuration file
• -S, --save-config - Save current options to configuration

Other

• -h, --help - Show help message
• -V, --version - Show version information

Examples

Scan a different network range:

lhssh -n 10.0.0. -b 1 -f 50

Quick scan with short output:

lhssh -p

Connect as different user:

lhssh -u admin 152

Execute command on all discovered hosts:

for ip in $(lhssh -p); do
    echo "=== Host .$ip ==="
    lhssh $ip hostname -f
done

Use with lhssh-cmd for parallel execution:

lhssh-cmd "df -h"  # Run on all discovered hosts

Configuration

lhssh stores its configuration in ~/.lhssh.conf. You can edit this file directly or use the built-in options.

Configuration Variables

# Network prefix (must end with dot)
LOCALHOST_HEAD='192.168.1.'

# IP range to scan (last octets)
LOCALHOST_START_IP=50
LOCALHOST_END_IP=230

# SSH login username
LOGIN_USERNAME='root'

# Display preferences
SHORT_DISPLAY=0        # 0=detailed, 1=IPs only
SUPER_SHORT=0         # 0=full IPs, 1=last octet only

# Timeouts (in seconds)
SSH_CONNECT_TIMEOUT=10
SSH_SESSION_TIMEOUT=600

# Features
COLOR_OUTPUT=1        # 0=disable, 1=enable
PARALLEL_SCAN=1       # 0=sequential, 1=parallel

Creating Default Configuration

Generate a new configuration file with default values:

lhssh -S

Editing Configuration

lhssh -e  # Opens in default editor

Advanced Usage

Combining Short Options

lhssh supports combining short options:

lhssh -vp  # Verbose + supershort display

Custom Network Scanning

Scan a specific range on your current network:

lhssh -b 100 -f 200  # Scan .100 to .200

Batch Operations

Run commands on multiple specific hosts:

for host in 152 153 160; do
    lhssh $host "systemctl status sshd"
done

Integration with Other Tools

Use lhssh output with other commands:

# Find hosts with specific service
lhssh -p | xargs -I{} sh -c 'lhssh {} "systemctl is-active nginx" 2>/dev/null | grep -q active && echo {}'

# Copy file to all hosts
for ip in $(lhssh -p); do
    scp myfile.txt [email protected].$ip:/tmp/
done

Troubleshooting

No hosts found

1. Check network connectivity:

ip addr show
ping 192.168.1.1

2. Verify SSH service on target hosts:

systemctl status sshd  # On target host

3. Test scanning tools:

which ssh-keyscan nc
ssh-keyscan -T 1 192.168.1.1

4. Try verbose mode:

lhssh -v

Connection issues

1. Check SSH keys:

ssh-keygen -t rsa  # Generate if needed
ssh-copy-id user@host  # Copy to target

2. Verify username:

lhssh -u correctuser 152

3. Increase timeout:

lhssh -t 30 152  # 30 second timeout

Performance issues

1. Disable parallel scanning:

# Edit config
lhssh -e
# Set PARALLEL_SCAN=0

2. Reduce scan range:

lhssh -b 100 -f 150  # Smaller range

Security Considerations

• lhssh uses key-based authentication only (PasswordAuthentication=no)
• Configuration file is created with 600 permissions
• SSH host key checking is set to accept-new for convenience

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test thoroughly
5. Submit a pull request

Version History

v2.0.0 (Current)

• Complete refactor to remove external dependencies
• Added parallel scanning support
• Improved error handling and logging
• Enhanced configuration system
• Better shellcheck compliance

v1.0.0

• Initial release with nmap dependency
• Basic scanning and connection features

License

GPL-3 License - see LICENSE file for details

Support

For issues, questions, or contributions:

• GitHub Issues: https://github.com/Open-Technology-Foundation/lhssh/issues
• Email: [email protected]