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Raw Print Server vs. LPR/IPP: Which Should You Choose?

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Raw Print Server: Complete Setup Guide for Windows and LinuxA raw print server accepts print data over the network and forwards it directly to a printer without modifying or interpreting the print job. This is often referred to as “raw printing” or using the “RAW” protocol (commonly TCP port 9100). Raw print servers are widely used in offices, manufacturing, and retail environments because they are simple, fast, and compatible with a wide range of devices and print languages (PCL, PostScript, and many vendor-specific formats).

This guide covers concepts, benefits, security considerations, and step-by-step setups for both Windows and Linux environments. It’s aimed at system administrators and technically-minded users who need a reliable, low-overhead print server.

Why use a raw print server?

  • Simplicity: The server does not interpret or alter the print data — it simply passes bytes from client to printer.
  • Speed: Minimal processing overhead yields faster job delivery for supported print languages.
  • Compatibility: Works with many network-enabled printers and legacy devices that accept raw TCP spooled data.
  • Control: Centralizes print access and allows monitoring, queuing, and access control at the network level.

Key concepts

  • Raw printing protocol: Typically TCP port 9100 (also called HP JetDirect, AppSocket).
  • Spooling vs. passthrough: Raw servers usually provide little or no spooling/processing; they are primarily passthrough devices. Some implementations add queuing and logging.
  • Print language: Clients must send printer-ready data (PCL, PostScript, or vendor-specific commands). If client software sends standard document formats (PDF, DOCX), conversion must happen on the client or on a printing gateway that supports transformation.
  • Authentication & access control: Raw port access should be secured via network controls, firewall rules, or by placing the print server on a trusted VLAN.

Preparation and general best practices

  • Verify printer supports raw TCP printing (most network-ready printers do).
  • Determine IP addresses or hostnames of printers and servers.
  • Reserve static IPs for printers or set DHCP reservations for predictability.
  • Open TCP port 9100 on any firewalls between clients and the printer, only where appropriate.
  • Consider using print queues and logging on the server if tracking or retrying failed jobs is required.
  • Secure the environment: use VLANs, firewall rules, and, where possible, IPsec or VPN for remote printing. Avoid exposing raw printer ports to the public internet.
  • Have vendor drivers or PPDs available for client systems when required.

Part 1 — Setting up a raw print server on Windows (Server or Desktop)

This section explains two common approaches on Windows: using built-in Windows Print Server features (with a TCP/IP port configured for RAW) and using third-party utilities for simple passthrough.

A. Built-in Windows Print Server (Windows Server / Windows ⁄11)

  1. Install the Print Server role (Windows Server) or add printers via Control Panel (Windows Desktop).
    • On Windows Server: Server Manager → Add roles and features → Print and Document Services → Install “Print Server”.
  2. Open Print Management (printmanagement.msc).
  3. Add a new Printer:
    • Right-click “Printers” → “Add Printer” → choose “The printer that I want isn’t listed”.
    • Select “Add a printer using a TCP/IP address or hostname”.
    • Device type: TCP/IP Device.
    • Hostname or IP address: enter your printer’s IP.
    • Uncheck “Query the printer and automatically select the driver” if the printer does not respond to SNMP or if you prefer manual driver selection.
  4. Configure the port:
    • On the “Port” step, choose “Create a new port” → Standard TCP/IP Port → Next.
    • Enter the IP and choose “Custom” → Configure Port.
    • Protocol: Raw. Port Number: 9100 (default).
  5. Install appropriate driver or use a generic/text-only driver when sending preformatted job streams.
  6. Optionally share the printer or publish it in Active Directory.
  7. On client machines, connect to the shared printer or add a TCP/IP printer using the same RAW port method if you prefer direct IP printing.

Notes:

  • Windows print spooler will accept jobs and forward raw data unchanged when the port is configured as RAW.
  • For PostScript or PCL jobs, install the matching driver/PPD for best results.

B. Lightweight passthrough tools

For a very small environment where you need a simple network-to-serial or network-to-network passthrough, third-party utilities (or small services) can be used to forward TCP 9100 to a printer. Examples include socat, netcat (ncat), and dedicated print-forwarding apps. These are more common on Linux but can be run on Windows (via Cygwin, WSL, or native ports).

Part 2 — Setting up a raw print server on Linux

Linux offers flexible options: CUPS can be configured for raw queues, and simple TCP port listeners can forward data. Below are two common setups: CUPS raw queue and a minimalist socket listener.

A. CUPS with a raw queue

CUPS (Common UNIX Printing System) is the standard print system on most Linux distributions. You can create a raw queue so CUPS does not perform filtering — it forwards client data directly to the destination.

  1. Install CUPS:
    • Debian/Ubuntu: sudo apt update && sudo apt install cups
    • RHEL/CentOS/Fedora: sudo dnf install cups
  2. Start and enable CUPS:
    • sudo systemctl enable –now cups
  3. Open CUPS web interface: http://localhost:631 (or configure remotely by editing /etc/cups/cupsd.conf and allowing access).
  4. Add a printer:
    • In the web UI: Administration → Add Printer.
    • Choose “AppSocket/HP JetDirect” or “AppSocket” as the device.
    • Connection URI format: socket://PRINTER_IP:9100 or socket://printer.example.local
    • When prompted for driver, choose “Raw” or “Generic -> Raw Queue” (this prevents CUPS from filtering or converting jobs).
  5. Save the printer. CUPS will forward incoming jobs unchanged to the socket destination.
  6. Configure sharing, ACLs, and access control in cupsd.conf as needed.

Notes:

  • With a raw queue, clients must supply print-ready data. If you want server-side conversion (from PDF, DOCX, etc.) add appropriate filters or allow CUPS to use drivers/filters.

B. Minimal raw forwarding with socat or ncat

For simple pass-through without CUPS queuing:

  1. Install socat or ncat (nmap-ncat).
    • Debian/Ubuntu: sudo apt install socat
  2. Run a forwarding service that listens on a local TCP port and forwards to printer IP:9100:

Example with socat:

sudo socat TCP-LISTEN:9100,reuseaddr,fork TCP:PRINTER_IP:9100
  • This binds local port 9100 and forwards incoming connections to the printer’s 9100.
  • Use systemd to run as a service for persistence.

Example systemd unit (replace PRINTER_IP):

[Unit] Description=Raw Print Forwarder After=network.target [Service] ExecStart=/usr/bin/socat TCP-LISTEN:9100,reuseaddr,fork TCP:192.0.2.100:9100 Restart=always [Install] WantedBy=multi-user.target

Notes:

  • This approach provides no spooling. If multiple clients connect simultaneously, the printer may reject concurrent sessions; consider adding a small queuing layer if concurrency is needed.
  • Use firewall rules to restrict access to the forwarder.

Security considerations

  • Do not expose raw printing ports (9100) to the public internet.
  • Restrict access by IP, VLAN, or firewall to trusted clients only.
  • Use network segmentation (VLANs) so printers are on a controlled network.
  • For sensitive environments, consider IPsec, VPN tunnels, or TLS-wrapped print protocols where supported.
  • Enable audit logging on the print server if job tracking is required. CUPS supports logging; Windows Print Server can log via Event Viewer or third-party tools.
  • Update printer firmware and server OS regularly to mitigate vulnerabilities.

Troubleshooting common issues

  • Printer not responding:
    • Verify printer IP and that the device accepts raw TCP on port 9100.
    • Test with telnet or netcat: telnet PRINTER_IP 9100 (or ncat PRINTER_IP 9100).
  • Jobs stuck in spooler:
    • On Windows: restart Print Spooler service; check driver compatibility.
    • On CUPS: check /var/log/cups/error_log and run cupsctl --debug-logging for more info.
  • Garbled output:
    • Ensure job data is in a printer-native language (PCL/PostScript). If using generic/text drivers, output may be incorrect.
  • Concurrent job failures:
    • Some printers accept only one raw TCP connection at a time. Use a queueing layer (CUPS or a spooler) to serialize jobs.
  • Permissions/access:
    • Check firewall rules, SELinux/AppArmor policies, and cupsd.conf or Windows share permissions.

Examples and practical scenarios

  • Point-of-Sale receipts: Many receipt printers accept raw ESC/POS commands over TCP 9100. Use a raw queue so the server does not alter ESC/POS bytes.
  • Label printers: Often expect vendor-specific binary streams — raw forwarding preserves exact bytes.
  • Networked legacy printers: A raw print server can allow modern clients to send printer-ready jobs without installing complex drivers on each client.

Managing and monitoring

  • Windows: Use Print Management to view queues, jobs, and set policies. Event Viewer holds logs for troubleshooting.
  • Linux/CUPS: Use the CUPS web UI, log files in /var/log/cups, and tools like lpstat and lpq to monitor queues.
  • Third-party monitoring: SNMP can monitor printer status, supplies, and errors (separate from raw port). Combine SNMP monitoring with raw forwarding for better oversight.

When not to use raw printing

  • When clients cannot produce printer-ready streams (e.g., many users sending DOCX/PDF without drivers).
  • When you need format conversion, text extraction, or server-side rendering — use CUPS with filters or a print server that supports conversion.
  • When secure confidentiality and encrypted transport are required and the printer or environment does not support secure tunnels.

Summary

  • A raw print server forwards printer-ready byte streams over TCP (commonly port 9100) with minimal processing, offering speed and compatibility for many networked printers.
  • On Windows, create a Standard TCP/IP Port configured for Raw (port 9100) or use the Print Server role; on Linux, create a CUPS “Raw” queue or use socat/ncat to forward connections.
  • Secure raw print services with network restrictions, updates, and monitoring. Use spooling/queuing when multiple clients or job retries are required.

If you want, I can provide: (a) step-by-step screenshots for Windows or CUPS, (b) a ready-to-use systemd unit file and installation script for a socat-based forwarder, or © sample troubleshooting commands tailored to your printer model.

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