Yesterday I wanted to connect to a wireless network with my N900. Unfortunately this was an IPv6-only network.
I haven't figured out how to configure IPv6 on the N900 yet, maybe someone can give me a hint. I've already looked at the kernel modules, but "ipv6" seems to be missing. Is there any repo I have to add?

Thanks in advance!

There is no IPv6 support unless you compile a custom kernel.

https://bugs.maemo.org/show_bug.cgi?id=356

This is definitely very sad. Even my old Symbian phone supported IPv6.
Compiling a custom kernel for the N900 is not an option at all (I do that for my desktop machines, but x-compiling and that kinda stuff is a pain in the butt).

I hope this is gonna change in PR 1.2. There is no need for an UI ATM, as this an advanced option. But a kernel module and IPv6-aware userspace (busybox) would definitely be nice - it's just a matter of configuring build parameters.

If anyone else is interested in this: I found out that IPv6 is provided by extra kernel modules.
See http://wiki.maemo.org/Kernel_Power for more information.

It's even weirder considering this:

http://people.nokia.net/~patil/Nokia/N900-IPv6/

At least someone is apparently working on it:

https://garage.maemo.org/projects/n900-ipv6/

I don't know why wifi and 3G are separate though once you get a network driver ...

Supposedly IPv4 exhausts addresses next year...

IPv4 has been supposedly exhausting the next year for several years now. When I first started using IPv6 at my home (~6 years ago), that was the primary reason.. evidenced by the fact that my ISP then only gave me NATted v4 connectivity.

But indeed, IPv6 by default would be nice, I think I actually had that working already on an N810.

Did anyone try the IPv6 with this? Does it "just work" with the new kernel, or does it require something else?

I did, it works out of the box. You need to install the tools like iproute and such to configure tunnels though.
I've used aiccu to get my SixXS tunnel working. I needed to compile it on scratchbox first as the debian armel package didn't want to install. You can find the deb package for N900 here: http://fournier.nl/aiccu_20070115_armel.deb. After creating a valid config file, it works out of the box.

Following your lead I registered myself at SixXS, got accepted and after requesting a tunnel I would like to start testing.
But I have problems installing your aiccu deb file.

How did you install it ? What repos did you enable ? apt-get always sees dependencies but refuses to install them. When I try it manually, it seems other dependencies but again it refuses. Any hand you can give here ?

Thanks

edit: Can you also include a (cleaned) version of your aiccu config file and how you use it ? Startup ? Manual/deamon etc ... ? If I can get it working I wouldn't mind putting all info in the SixXS wiki, for the greater good of the N900 community.

I might have used extras-devel, but at least extras-testing.

Config (/etc/aiccu.conf):
username xxxx-SIXXS
password xxxxxx
protocol tic
server tic.sixxs.net
ipv6_interface sixxs
tunnel_id Txxxx
verbose true
daemonize true
automatic true
requiretls false

I start it by hand, but you could write a script to do it automatically using /etc/network/interfaces and the post-up command. I'm discussing with SixXS whether or not they want it in their download section.