How to troubleshoot Network slow down on Firewalla router

Authored by: Support.com Tech Pro Team

1. Introduction

Physical Connections

How the firewalla is connected to your network can influence your network speed. Some of the basic checks

Try to switch to a different ethernet cable. A bad cable will slow down the speed.
Try to connect firewalla to a different port on your router or switch.
If you have the Blue, check the light indicator on your router and make sure it is indicating Gigabit speed.
If you have a spare dumb switch, try to connect that between Firewalla and your router. We have seen the router port not switching correctly when directly connect to firewalla.
Make sure the firewalla is connected as close as possible to the router. (via a switch is okay)
The Firewalla box should be connected to your main router, or off a switch connected to the main router. Do not connect Firewalla to a satellite unit of a meshed router, or a network extender. (please see https://firewalla.com/install for details)
Please be aware that the maximum packet processing speed of Firewalla Red is 100 Mbps and Firewalla Blue is >500 Mbps. If your Internet connection is greater than 100 Megabits, you should consider getting a Blue, which is optimized for power and speed.

Software

If your network is slow down to under 30Mbps, your router is probably not compatible with Firewalla. Check Router Compatibility here.
If you are using a meshed router please see https://help.firewalla.com/hc/en-us/articles/360008005173-About-Mesh-Routers
Please also make sure your router's firmware is up to date. We have seen one case with NETGEAR R6220 where the router firmware was slowing down firewalla to 30% normal throughput. Upgrading to the latest firmware solved the problem.
If you have Fing/circle/Cujo/Bitdefender/PiHole or similar products on your network, please see https://firewalla.com/compatibility for details.
If you have a router within a router or networking device (access point, bridge devices, extenders) under your network, please make sure they are not monitored. (Tap on devices->tap on the device->scroll to the bottom and turn off monitoring)
If you have restricted or filtered DNS on your router. (such as Merlin) Please do not filter DNS requests from Firewalla.

More ways to check

Check to see if you have QoS turned on that may limit the speed of the ethernet ports on your router. We have seen this on the Asus router.

Rules

If your network used to work and suddenly slows down. Please check your rules button, under it, make sure you are not blocking "CDN" or like sites ... Try to pause the rules and make sure they are not slowing you down.
There are things like "Adblocker-blocker", try to turn off ad-block, and see if things are faster.

Others

We have seen routers like the Linksys E9500 when firewalla is connected directly to the router, there is a visible slowdown. Connecting firewalla to a switch (and all other devices are also on that switch) fixed the slow problem.