A new router (Soekris, Draytek and NanoBSD)

A few months back I wrote about building a new server. It turned out to be more complicated than I thought, but 5 months on it’s still working well. Over the last few weeks I’ve been working on my next project – replacing my router.

The old router was an old dual CPU Pentium 3 machine with a couple of small SCSI hard disks in it. It was a full tower case and took up a lot of room and made a lot of noise. And, surprisingly, the power consumption was pretty similar to the server I recently built (which has way more in it). It even still had the original Speedtouch USB modem that BT once gave to me. So it had to go.

I spent quite some time deliberating the way forward. I could have gone for a domestic router like most other people do, but I’m a geek, and I like the flexibility of doing it myself. But at the same time, a small sized unit, with low power requirements, and no noise, is what I wanted. The solution came in the form of a Soekris net5501.

I went for the net5501-70 which has a 500Mhz CPU and 512MB of RAM. Not a lot by today’s standards, but more than sufficient for what I needed. And incidently, it’s quicker than the old router. I got the model with a case, and got the mounting brackets for a hard drive (which although I don’t intend to use at this stage, it was cheaper to get it now than later). I also purchased a pair of 4GB SanDisk Extreme III Compact Flash cards to run the thing from. It’s worth noting that Soekris recommend SanDisk CF cards, and they’re peanuts at play.com.

The next point to consider was how to connect to the ADSL line. I could have stuck with the USB modem, but the drivers were aging, I wasn’t sure if it was the cause of the odd disconnections and failures to reconnect that I’d been getting. I looked at internal ADSL cards, but it seemed to be a bit of a gamble as to how they worked and if I’d be able to get the right drivers. In the end I settled on the Draytek Vigor 110.

The Vigor 110 is basically just a PPPoA to PPPoE bridge. PPPoE isn’t widely used in the UK, but is in other parts of the world, so the support in FreeBSD was good (via ppp and the ng_pppoe module). It worked perfectly. It really was just a case of plugging it in and pointing ppp at it – no configuration required! And, just like the USB modem, it gives the router IP directly to the PC, so there’s no messing around to get that working either.

Longer term I plan to fill the net5501’s PCI slot with a wireless card, but I haven’t decided which to go for yet. This would turn the unit in to my wifi access point as well, but for now I’ll just stick with the separate one. I’d welcome advice on cards that are supported by FreeBSD.

So, that’s hardware all sorted. Next came the software. If you’ve been following my other posts you’ll know I’m a big fan of FreeBSD, so it’s pretty clear what route I was going to take here. But given the use of CF cards I had to approach things differently. I also wanted to be able to power the system off without causing any filesystem problems, so this required the card to be mounted read-only.

NanoBSD to the rescue! NanoBSD is a script that builds an image containing FreeBSD that can be written directly to a CF card (or anything else, really). It’s customisable, and I wrote a few bits to pull down the packages I wanted, and to make some configuration tweaks. It has a read-only root filesystem on the card, and uses memory-backed filesystems for /var and /etc. Config is stored in a separate partition on the disk and is copied to the memory-backed /etc during the boot process. But the best bit is the way it handles upgrades.

Upgrades are neatly done by having two root filesystems on the card. When you’re running off one you’re free to upgrade the other. NanoBSD generates two images; one for the entire card, and one that can be written to a single root filesystem. It also provides a script to write the image to the card and update the boot loader to boot from the right partition. So upgrading is as simple as re-running the NanoBSD script, writing the new image to the “other” partition, and rebooting. It can all be done live, and the only downtime is the time taken for a reboot (which is under a minute).

Of course, to use NanoBSD you need another system to do the builds on. Fortunately I’ve got a nice beefy server that can handle the job (although it took a few hacks to build the i386 image on an amd64 system). I’ve also got a nice Tinderbox setup which I already use for testing ports and which provided a nice supply of up-to-date packages.

So I’m happy, at last. Apart from my wifi access point I’ve managed to replace all my aging, power hungry, noisy equipment with nice new stuff. I guess I’ll be doing it all again in a few years 😀 .