Printing Across VLANs: A Secure and Scalable Solution

In my previous configuration, I used a CUPS server with multiple network interfaces to enable printing from computers on restricted networks onto the printer located in the admin network. However, after some research and exploration, I discovered a more efficient way to achieve this goal by utilizing VLANs for network segmentation.

Creating a Dedicated Printer VLAN

To start, I created a dedicated "printer" VLAN that can only communicate with the internet but is isolated from other VLANs. Networks from which I want to enable printing, are configured to allow creating connections to the printer VLAN. This ensures that printing traffic within the restricted networks cannot accidentally traverse to other parts of the network, while computers can print to the printer. The printer VLAN is now the primary focus for setting up the UDP proxy container.

Configuring the UDP Proxy Container

To enable printing across multiple networks, I created a Linux container, for a UDP proxy, with network interfaces on both the printer VLAN and any additional VLANs that need to support printing. In this setup, the UDP proxy container acts enable notifications of the printers on the printer VLAN to computers.

Here's an example of how to configure the UDP proxy relay using the udpbroadcastrelay command:

# Configure the first relay for NetBIOS
./udpbroadcastrelay --id 1 --port 137 --dev printer-vlan-interface --dev computer-vlan-interface -f
# Configure the second relay for NetBIOS
./udpbroadcastrelay --id 2 --port 138 --dev printer-vlan-interface --dev computer-vlan-interface -f
# Configure the third relay for SSDP
./udpbroadcastrelay --id 3 --port 1900 --dev printer-vlan-interface --dev computer-vlan-interface --multicast 239.255.255.250 -f

Unlock Seamless Remote Access: The Power of Split DNS with Tailscale

 As a remote worker or someone who frequently collaborates with others on different networks, you're likely familiar with the challenges of maintaining seamless communication and connectivity across various environments. One innovative solution to this problem is split DNS combined with Tailscale, a powerful tool for creating secure, managed tunnels between devices.

What is Split DNS?

Split DNS refers to a configuration approach where your device uses different DNS servers depending on whether you're connected to your local network or an external network (such as the internet). This allows your device to resolve names and access resources locally without relying on the DNS servers associated with the external network, which can be slower and less secure.

How Tailscale Works

Tailscale is a popular tool for creating managed VPN tunnels between devices. It provides a simple and secure way to connect to remote networks while ensuring your data remains encrypted and private. When you install Tailscale on multiple devices, it creates a network of encrypted connections that allow you to access each other's computers as if they were directly connected to the same local network.