Adventures with DD-WRT and IPv6 (with a dash of TomatoUSB)

A little under a year ago, I decided two things: first, that it was about time my ageing home network got GigE and 5GHz wireless-N (dual band, of course, to support devices that would only do 2.4GHz); and second, that I would separate the jobs of BEING my network from CONNECTING my network to the internet (since I couldn’t find a good router which would meet these requirements AND had an ADSL modem in it).

So I bought a Linksys/Cisco E3000, made it the backbone of my network and connected it to the internet via my ISP-supplied ADSL modem.

Then an unfortunate incident happened which involved the Linksys/Cisco setup CD, an unwanted but non-removable guest WiFi network, and me swearing a lot.

The time had come (after about 16 hours!) to put DD-WRT on my router. As this post describes, choosing a version of DD-WRT that won’t “brick” your router (as the developers like to describe it) is treacherous to say the least. I eventually settled on dd-wrt.v24-16758_NEWD-2_K2.6_mega (specifically, the nv60k version). Despite the trepidation caused by the dire warnings on the web site, the flashing went well, and I’ve been pleased with DD-WRT ever since. Until…

Last week, I had a 40Mbit/sec fibre broadband connection installed. Amongst other things, my new ISP provides me with a block of IPv6 addresses. Actually 2^80 of them. I seriously need to think about what I’m going to do with them all.

My excitement at having 1,208,925,819,614,629,174,706,176 IP addresses was somewhat dampened when, after a day or so of fiddling and researching, I discovered that DD-WRT’s supposed IPv6 support was limited to the various types of v6-over-v4 tunnels (e.g. Hurricane Electric). Specifically, the PPP daemon doesn’t support IPv6 – so this might just be an issue for PPPoE users. There was no way for me to use all that space natively.

It should be noted here that even if you do want to use a tunnel to reach the IPv6 internet, you will still need to write startup scripts for DD-WRT to load the kernel module (the “Enable IPv6″ checkbox doesn’t actually do anything), start radvd (the “Enable radvd” checkbox doesn’t actually do anything), configure the tunnel interfaces and WAN IP addresses, etc. And even after all of this, you’ll find that the IPv6 user tools (ip6tables, ping6, traceroute6, etc.) aren’t installed, so you’ll have to locate them and hope you have room on your device somewhere.

So the time has come to make the move to TomatoUSB. To some extent, this suffers from the same issues as DD-WRT when it comes to variants, etc., but the information is more logically presented, and there do seem to be fewer choices and fewer potential traps. After looking at the comparison of “mods” on Wikipedia, I chose Toastman’s mod. It seems to have all the features I wanted and he seems to do frequent builds with all the latest updates and patches – in fact, the latest build (1.28.7494.3) was made only 6 days ago. This compares well with DD-WRT which doesn’t appear to have had any real active work/releases for a year or so now.

My first impressions of TomatoUSB are positive. The GUI feels snappy, and has most of the same features as DD-WRT. The real-time bandwidth monitor is definitely prettier than DD-WRTs. And, most importantly, the IPv6 support works out of the box.

TomatoUSB IPv6 configuration screen

Out-of-the-box, ip6tables is configured to allow ICMP packets of every type (so I can ping all my machines from various online ping sites), but disallow all inbound traffic. So, Linux ip6tables bugs aside, I’m secure by default, which is nice. There doesn’t seem to be a GUI interface to setup firewall rules for IPv6, so I guess if I ever to want to let anything in, I’ll have to ssh to the router and do it by hand – but why would I ever want that?

And that’s that. I took under 2 hours to flash TomatoUSB, reproduce all my configuration on it, and get IPv6 working. Nice. I can now browse,, and I get a dancing turtle when I visit Also, this:

Results from

One last thing: don’t forget to enable IPv6 privacy extensions on all of your hosts!

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2 Responses to Adventures with DD-WRT and IPv6 (with a dash of TomatoUSB)

  1. Hi, thanks for the informative post.

    I’ve about given up on trying to add IPv6 to DD-WRT. Are you still happy with Tomato USB and the Toastman mod?

    • Danny says:

      I am. Some bits of it are prettier than DD-WRT and some bits are less pretty – but the native IPv6 support works and appears to be completely stable. In fact, it’s about time I upgraded to the latest build… :-)

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