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ADSL routers running open Linux in the next future?

While certainly there are a lot of home-class ADSL routers already running Linux, most of them are “closed” Linux, provided by the hardware manufacturer and that cannot be customised over a certain point.

I do have a router currently running OpenWRT, a Linksys WRT54GL, but I don’t use it as ADSL router, I use it as a wireless client that routes the wireless network on a wired network segment, the one where Farragut, Enterprise, Klothos and Prakesh are located. I needed to use this network setup because I can’t reach my office with suitably good phone cables that allows me to stay connected with a decent SNR, so I need to connect the wired segment to the wireless network that then gateways me to the WAN. And I had to use an OpenWRT-based WRT54GL because the cheapest router capable of understanding that the WLAN is where the default gateway is was at €300, which is quite too much for me.

OpenWRT is a nice piece of software, I tried three versions of it up to now, because I fucked up two times, once while I was trying the safe way to upgrade the whole version, and once when I tried to upgrade only the packages, but every time, reflashing and reconfiguring didn’t take more than a couple of hours, and every time I make the configuration cleaner and nicer.

I don’t use the firewall, for instance, and I map all the five ports of the switch to the LAN, as I don’t need to distinguish between WAN and LAN on there, the WAN is on the wireless network, but I do install extra services like CUPS and Avahi, both acting as reflectors for broadcasts, so that the services available on the wired and wireless networks can be seen on the respective other network. I also wrote a simple sh script to update DynDNS, although the current one I have here is designed to run on Whiterussian (and whatever the previous version was called, I forgot), while for the new Kamikaze I should update it to use the configuration files rather than the nvram. I’ll work on that in the next days and then upload the new version of the script.

Anyway, I was thinking lately about the ability to run OpenWRT on an ADSL router with onboard modem. I didn’t know how well supported ADSL modems are with OpenWRT, and I pretty soon discovered that even if there is some support, it is not yet possible to use most ADSL routers in their full blown capacities. Luckily this might change in the future, as I see that there is work in progress to support the Texas Instrument AR7 that at least D-Link uses for their latest routers models.

Why would I care of an OpenWRT-running ADSL router? Well, my first ADSL router was a D-Link DSL-500, running ATMos operating system, a decent piece of software, albeit closed source, you could access most features through the CLI interface either by telnet or by serial port, even when the web interface ruined them. The problem with it was that either the networking core or the hardware weren’t stable enough, and when running bittorrent or any other software sending and receiving lots of UDP packets, the router would crash down. This was unbearable on the long run, and thanks to Florian Steinel, I’m now using a 3Com router.

The 3Com router seems to have nicer hardware and handles the load way better. It also is an all-in-one router with WLAN, so I don’t need a standalone access point. The problem it has is with the software, or probably just with the web interface of it (there’s no CLI here, but I’m sure the underlying software is probably quite okay). For instance, the port forwarding table does not consider the network mask setting the router has: it only takes the first three octets of the router’s IP and allows to choose only the fouth for any forward rule. This means not only that if you set the route to you can’t forward ports to devices in the same network with IPs like, but you can forward ports to while using as IP address, so the limitation was not designed to limit you to a single subnetwork, it’s just that the forwarding page does not give a crap about the network mask at all; I tried to explain that to 3Com support, but they are quite worse compared to when I had an UsRobotics modem – then they were very good – and their level 2 support techs weren’t able to understand how I divided my network in two subnetworks… Also, the router does not provide any IPv6 feature.

While I’m almost totally satisfied with the current setup, and I’ll probably run this router for many years (minus failures), I find it somewhat restraining, and for instance I would welcome a firmware for it that would allow me to get IPv6 addressed for the internal network, NATing only the IPv4 requests, or at the very least a firmware which would allow me to make the subnetworks two /24: a /28 is pretty limited especially when you also use it for virtual machines.

So, I’ll certainly be looking forward for AR7-based routers in the next years, in the unfortunate case I need to switch router again (which I really hope won’t happen, I had enough hardware failing on me this year, and I still have to bring Klothos back from the dead with a new SATA controller; help is welcome :P).

Comments 3
  1. I’ve had a Lynksis ADSL2MUE for a while now, it works alright as-is but I definitely be interested in playing around with OpenWRT if progress happens on AR-7 support. I had checked a while ago and it felt it would take quite some time before something usable comes out, so I’m quite pleased to see so much progress has been made!If you only use 2 subnetworks, why don’t you make them /25 instead of /28 ?

  2. I don’t know your layout or European electrical standards so don’t know whether this might help or not, but at least here in the US, standard phone cable is only cat-3, and many of the extension cables you can buy are simply untwisted/unshielded flat quad-conductor wire, which of course is /terrible/ for noise.Back when I had DSL, I lived in a trailer, with the police liking to sit in their cruisers just behind my back fence, a few feet away. As I was in a trailer, I had simply plugged my plain old extension cable (flat untwisted/unshielded wire) into the NID (Network Interface Device, the device telcos here in the US have by law, that interfaces the telco maintained network with the homeowner maintained network). I kept having problems with the police radio transmissions punching thru and killing my DSL.First thing I did was scrounge up some shielded audio cable, replacing the flat-cable phone extension with it, and of course grounding the shield on at least one end. That worked great, but was only the single line, voice with piggybacked DSL.Later, I moved, and while I didn’t have the strong police radio interference at the new location, I needed more than the single pair, as I got DSL from a different provider and had a separate dedicated DSL/data line. By this time I knew a bit more about twisted pair technology, and simply purchased and wired up a couple pair in a length of standard cat-5 Ethernet cable. That worked well too, but to be fair, I didn’t have the same strong interference, so I can’t accurately say it worked /as/ well, as I just don’t know that.Later still I switched to the cableco, first for Internet service when it came available, then voice when it came available as well. I still have them for Internet and am decently happy with it, but recently switched to VoIP for voice. (The VoIP quality isn’t as good as the cableco’s digital phone, but it’s not much worse than the old analog telco was or than cell service, and both has far better features and is cheaper too, so I’m happy with it too.)So anyway, if all you’ve been trying is standard phone cable, and it’s as crappy over there as it is here, try standard cat-5 Ethernet cable, or shielded audio cable. It certainly fixed the noise issues I had here! Of course, as long as what you have is working, and if you are already getting all the speed your DSL connection offers, there’s little reason to change it now, but for further reference, if you haven’t already tried that, of course (but if it’s noisy enough that cat-5 or shielded doesn’t work, I have trouble seeing how the WIFI’s working in the environment either).Duncan

  3. There is one DSL modem router in France, it is made by Efixo for Neuf Cegetel, the second largest ISP in France.It is called Neuf Box 4 (or NB4), and the GPL sources have been published at…A unofficial community has formed at and aims at creating an alternative fully opensource firmware for this DSL modem router.It will be based on OpenWRT, and one of the developers of OpenWRT is helping us ;)They even talked about it on…Just wanted to share this with you, I hope more ISP will open up their modems and OpenWRT will run on them!

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