Replacing PC Engine Alix by Turris MOX

History and motivation

Since 2010, I used an Alix device as my home router/firewall, plus some basic services: DNS, ntpd, dhcpd... I installed Debian on it, and it provided so far a robust 'fire and forget' solution.

Though some problems started to pile up over the years:

1. The Geode LX processor in the Alix series isn't a full i686 CPU. Debian dropped support fo these, see https://www.debian.org/releases/stretch/i386/release-notes/ch-information.en.html

So I am basically stuck with Debian Jessie, which is EOL since mid-20201.

1. I got finally FTTH at home, and the 100Mbit/s of the Alix ethernet ports aren't enough to catch up all the speed of my connection.

2. The Alix board is really short on RAM: 256Mb only; so I can't even run Emacs on it.

3. The boot time of the Alix is long: full 3 minutes

So after 12 years, let's look at something more powerful, and still cheap on price and electricity consumption.

Choosing a new router

More specifically, I wanted:

1. Fanless

2. A 64 bits CPU

3. At least 3 LAN ports

4. SFP port or WIFI not really needed

Here the short list I came through, all around 200$:

1. A mini PC with Intel Celeron Quad Core and 4 LAN ports (Intel i225); it's called "J4125 industrial PC" on AliExpress and the brand is unknown; there are a lot of similar offerings on their web site

2. Banana BPI R64; if you don't do POE, you need a power supply with non standard plug dimensions.

3. Turris MOX; shipped with a customized OpenWRT called TurrisOS

4. Expressobin Ultra: similar SoC as the Turris MOX; OS shipped seems to be Armbian

Choices which may have been valid also:

1. ClearFog CN9130 Pro; sold by SolidRun. This is a high end router, a bit too overkill in features and pricy. But probably excellent for the SOHO market.

2. The last generation of Alix called APU2; this would have been the easy replacement choice. Has open source BIOS. A bit costly, but the nail in the coffin was lack of availability by the vendors at the time I wanted to buy.

I settled about the Turris MOX (modules A and C), bought through Discomp. The decisive arguments for my choice were:

1. a flexible, upgradable and open architecture
2. an active community exists around Turris hardware

Beginning with the Turris MOX

Mounting/unmounting the parts of this Lego like device is easy: https://www.youtube.com/watch?v=yL8Rpo0Wshc

First connexion is straightforward: https://docs.turris.cz/hw/mox/intro/

The MOX admin web interface (called Foris) is at http://192.168.1.1, which is often also the address of your ISP modem; in that case you have to change that last one to avoid conflict.

Foris is a wrapper around the standard Luci configuration tool of OpenWRT. It allows for a simple connectivity test, and manages additional packages or upgrades of TurrisOS (more on that below). But for more advanced configuration, Luci is unavoidable, be it the web interface or the command line. Notice that changes made through Luci can introduce inconsistencies with Foris, and so unexpected behaviour.

I never tried to get ipv6 from my ISP with my old Alix (I had a tunnel for that). The MOX was able out of the box to offer additional ipv6 addresses from my ISP /56 prefix to all my devices at home, good!

At first connection, Foris offers to upgrade its factory setup. This won't work because the factory release is too old wrt the proposed upgrade. You will have to use the reflash procedure from a USB drive to get the most recent version and allow upgrades from there. Entering the reflash mode is a bit tricky, you have to monitor a led on the other side than where the button to push (actually a paper clip hole) is located.

Hacking the Turris MOX

There is no serial DB9 port on the MOX like the Alix had, you have to use the GPIO connectors.

The serial/USB convertor must be at 1.8V, this is non standard. For 20$, I purchased a DSD TECH SH-U09C2 adapter. With this adapter you don't need to connect the VCC 1.8V GPIO pin.

Debian as a LXC container

The procedure to do that is explained here: https://docs.turris.cz/geek/lxc/lxc/

I connected a USB disk for Debian on the MOX and choose to share network with my container like that:

lxc-start -n turris-debian --share-net 1

So I was able to install Debian specific stuff I had on the Alix.