ENG | MikroTik: Blocking the BambuLab Printer (or Any Device) from Internet Access

TL;DR: When you switch BambuLab printer to LAN mode, you have to log out in OrcaSlicer or BambuStudio.

Introduction

In this blog post, I’ll guide you through the process of blocking a BambuLab 3D printer from accessing the internet using a MikroTik router. This is particularly useful for preventing unwanted firmware upgrades and ensuring the printer remains functional with third-party tools like OrcaSlicer.

Motivation

I did this as a reaction to this official blog post and explained in this youtube video. In basic BambuLab decided to close its ecosystem by blocking 3rd-party tools, such as OrcaSlicer, or at least most of it’s functionality making it incovenient to use.

In their official statement, they claimed:

Bambu Connect enables integration with third-party software, such as Orca Slicer by using the file transfer method shared in the wiki. Before announcing this change publicly, we shared it with the lead Orca Slicer developer to ensure alignment and collaboration. Moving forward, we remain committed to working closely with them and other partners to facilitate the integration of Connect software, creating a smooth and hassle-free experience for all users.

However, their actions tell a different story. While they publicly stated a commitment to collaboration, the OrcaSlicer developer revealed that they were informed of these changes just two days in advance, without being provided with the technical details or API keys needed to maintain functionality. This inconsistency between their statements and actions undermines trust in their communication and intentions.

Blocking the Printer

This command blocks connections from Bambulab 3D printer to internet based on MAC address.

# List firewall filter rules
/ip firewall filter print
# Add new rule
/ip firewall filter add chain=forward action=drop src-mac-address=80:65:99:c7:7c:f4 out-interface-list=WAN comment="Block 3D Printer from Internet"

Since there is a rule that allows already established connections, you will need to turn the printer off and on again for the new rule to take effect.

Switching the Printer to LAN Mode

This is straightforward step.

Troubleshooting Issues

Now, curiously, both BambuStudio and OrcaSlicer can see printer in LAN mode, but they can’t connect to it, when you enter pairing PIN. When I disabled firewall rule above and unplugged router from the outer world, LAN mode started to work. All I got was this error:

Failed connect to the printer
code: -6010
desc: Connection to the printer failed
info: Please check the network connection of the printer and Orca

I was curious where the problem is, slicer could see the printer, but can’t connect to it? Then I tried to enable logging on router. Only dropped packets were UDP packets to port 123 of length 76 bytes - the Network time protocol to synchronize time. Weird.

I allowed this traffic, so printer could get actual time. It did not help. Except no traffic from printer was now blocked. Firewall rules are:

12    ;;; Allow NTP traffic
      chain=forward action=accept protocol=udp dst-port=123 log=no log-prefix="" 

13    ;;; Block 3D printer internet access
      chain=forward action=reject reject-with=icmp-network-unreachable dst-address=!192.168.68.0/24 src-mac-address=80:65:99:C7:7C:F4 log=yes log-prefix="blocked-internet-access"

Then I somehow tried to logout from Bambulab account. Suddenly I was able to connect to the printer.

Summary

Blocking BambuLab printer from internet and switching it to LAN mode are straight forward steps. However it was not obvious to me that I have to log out from BambuLab cloud in slicer software. Hopefully someone finds this helpful.