Printer Proxy

A network traffic redirection solution for network printers that uses NAT and iptables to transparently redirect print jobs from a failed printer to a working replacement without requiring client reconfiguration.

Note: This software is currently in beta. The core network redirection functionality is stable and production-ready. Job monitoring and printer event logs are experimental features.

Installation

Install Printer Proxy via the official APT repository:

# 1. Add the GPG signing key
curl -fsSL https://jordonh18.github.io/printer-proxy/gpg-key.asc | sudo gpg --dearmor -o /usr/share/keyrings/printer-proxy.gpg

# 2. Add the repository
echo "deb [signed-by=/usr/share/keyrings/printer-proxy.gpg] https://jordonh18.github.io/printer-proxy stable main" | sudo tee /etc/apt/sources.list.d/printer-proxy.list

# 3. Install
sudo apt update
sudo apt install printer-proxy

Upgrading

sudo apt update
sudo apt upgrade printer-proxy

Initial Setup

1. Access the web interface: https://<server-ip>
2. Accept the self-signed certificate warning
3. Create an administrator account on the setup page
4. Log in with your new credentials

Overview

Printer Proxy operates at the network layer to intercept and redirect TCP print traffic destined for a failed printer to an alternative target. When a printer fails, the proxy server claims the failed printer's IP address as a secondary interface and applies DNAT rules to forward incoming connections to a working printer.

How It Works

                           ┌──────────────────────────────────────┐
                           │         Printer Proxy Server         │
                           │                                      │
                           │  1. Claims 192.168.1.10 as secondary │
                           │  2. Applies DNAT rule in iptables    │
                           │  3. Forwards traffic to target       │
                           └──────────────────────────────────────┘
                                          ▲           │
                       Print to           │           │ Forwarded
                    192.168.1.10:9100     │           │ to target
                                          │           ▼
┌──────────────────┐                      │           ┌───────────────────────┐
│   Client PC      │──────────────────────┘           │   Working Printer     │
│                  │                                  │   192.168.1.20        │
│  No changes      │                                  │   Receives jobs       │
│  required        │                                  └───────────────────────┘
└──────────────────┘

Features

Network Management

• Secondary IP Assignment: Dynamically assigns IP addresses to network interfaces
• NAT/DNAT Rules: Creates iptables rules for transparent traffic forwarding
• Port Support: TCP 9100 (RAW printing), with configurable port support

Printer Discovery

• mDNS/Bonjour: Discovers printers advertising via multicast DNS
• SNMP Scanning: Scans network ranges for SNMP-enabled devices
• Manual Entry: Supports manual printer registration

Health Monitoring

• Background Polling: Monitors printer availability via ICMP and TCP
• Health History: Tracks uptime/downtime over time
• Status Dashboard: Real-time status indicators

Automatic Updates

• Updates are delivered via APT repository
• Check for updates in the Settings page
• Updates are applied automatically with service restart

System Requirements

• Ubuntu 20.04+ or Debian 11+
• Python 3.9+
• Root/sudo access for iptables manipulation
• Network interface capable of multiple IP addresses

Development

# Clone repository
git clone https://github.com/Jordonh18/printer-proxy.git
cd printer-proxy

# Create virtual environment
python3 -m venv venv
source venv/bin/activate

# Install dependencies
pip install -r requirements.txt

# Run development server
python run.py

Building

# Build .deb package
./scripts/build-deb.sh

License

MIT License - see LICENSE for details.