Disable DHCPv6 on AVM Fritzbox

Posted by Kaya Kupferschmidt • Wednesday, January 25. 2012 • Category: Workstations
If you own a FritzBox router from AVM and use IPv6, this might be interesting for you. If IPv6 is enabled, all clients will get a IPv6 DNS server from the router. Although this might seem to be a nice feature, it creates problems if you run your own DNS server for your local net. All Windows clients first will ask the IPv6 DNS server configured from the FritzBox, and then ask other IPv4 DNS servers. This might be especially bad, if you configured some hostnames in your own DNS server differently for your local net than for the internet (this makes sense if you run some server in your net which is also accessible from the internet). In such situations you really want to get rid of that DNS server announced from the FritzBox.

Unfortunately this is not possible from the GUI, but you can disable DHCPv6 (which is used for announcing) by changing some config file on the FritzBox. So you need to do the following:

1. Enable telnet via #96*7*.
2. Login to your FritzBox with telnet fritz.box (or whatever address the FritzBox has in your LAN)
3. # cd /var/flash
4. # nvi ar7.cfg
5. Change the setting dhcpv6lanmode to dhcpv6lanmode_off_stateless
6. Disable telnet via #96*8*
7. Reboot the FritzBox

This should completely turn off the DHCPv6 server in the FritzBox.

Serviio DLAN Server on Debian

Posted by Kaya Kupferschmidt • Wednesday, December 28. 2011 • Category: Workstations
If you want to share your media collection (that is music, videos and pictures) in your LAN on multimedia devices like tablets, smartphones, TVs and consoles, you end up using either DLNA or UPnP. Because my devices support DLNA, I decided to give it a try to install a DLNA service on a Debian server. Googling around, I found some different implementations of which Serviio media server looked most primising. Implemented in Java it surely uses some more resources than some native C/C++ implementation, but it offers some nice features like plugins and device profiles. And it offers a pure server implementation without a GUI, which was very important to me for running it on a headless server.

Continue reading "Serviio DLAN Server on Debian"

Mercurial, finally!

Posted by Kaya Kupferschmidt • Saturday, August 13. 2011
When I started to work as a software developer, still during the time when I was studying, I made first contact with a source control system. Of course it was the highly respected Microsoft Source Safe. For me as a fresh developer, this was something really new, and I immediately started to like it. I even started to use it for some private projects and immediately saw the benefit of using it, even if you are the sole person working on a project. After that some years later, I made the experience with the old and famous CVS - but only to see how it was replaced by the far better new-kid-on the rock called subversion.

That was really something nice - supporting branching, atomic commits, nice integration in all relevant IDEs and of course TortoiseSVN, which became the de-facto standard for accessing subversion repositories with windows. There came even a clone for CVS called TortoiseCVS. Everything was much better than with Source Safe or CVS.

But after some time, it became clear, that branching (one of the best-selling features of subversion) just doesn't work - simply because merging doesn't work. With those problems in mind, even Linus Torvalds said that "Subversion is the most pointless project ever started". He was into something better called Git which is a distributed source control system. At more or less the same time a second project called Mercurial was started with the same ideas like Git. Both of them work in a completely distributed manner, such that everyone has a copy of the complete repository including all the history. Of course in this situation merging becomes a non-trivial part, and that is the reason why they are doing this so much better than subversion. Without robust merging and tracking branches a distributed version control system simply wouldn't work.

So today I finally made the switch to Mercurial with my private project, after I have been happily using subversion for several years. Luckily it is quite easy to convert a subversion repository to a mercurial repository. I also chose Bitbucket as a public hosting platform, so from now on everyone is invited to clone the Magnum repository which is available at https://bitbucket.org/dimajix/magnum.

Looking back, I think it was still the right decision first to move to Subversion and then to move to Mercurial/Git, simply because those projects weren't up to speed at that time.

Add NIS Client Support to ReadyNAS

Posted by Kaya Kupferschmidt • Saturday, February 21. 2009 • Category: Workstations
This guide is about how to setup probably any ReadyNAS device to act as a NIS/YP client. NIS/YP is a protocol that shares account information accross the network. In such an environment it is important that the ReadyNAS knows about all Linux and Windows account, so it can keep access rights on files in sync. If users had different numerical IDs on Linux clients and on the ReadyNAS, all files created from these clients wouldn't beb accessible on Windows machines any more, because the ReadyNAS wouldn't know which account the files belong to.

On Windows there is already a powerful solution, called Active Directory. This is already supported on the ReadyNAS, but there is no support for the corresponding UNIX protocol, which is NIS. Having a central account authority which manages both Windows and Linux accounts via Active Directory and NIS is very helpful in such mixed environments.

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Phun with Physics

Posted by Kaya Kupferschmidt • Wednesday, January 21. 2009 • Category: General

While browsing on OpenGL.org, I found a really nice educational (?) 2D physics simulator called Phun. The physics engine is a commercial multibody simulator, which seems to be new in the physics scene (at least I never heard of AgX before).

And now, don't waste your time on my blog, and Grab Phun here.

New 6bay ReadyNAS on the way

Posted by Kaya Kupferschmidt • Thursday, January 17. 2008 • Category: Workstations
I really like my ReadyNAS server - small, slick, multifunctional and superb support.

But there are two things missing: more drive bays and a more powerful CPU. But apparently the first point is being addressed with a ReadyNAS Pro device with 6 bays, as seen on CES 2008. I hope, they also spent a more powerful CPU to the device, so it will be able to outperform the Thecus devices. Those are a lot faster, but the firmware and support seems to be really bad.

Can't wait to get my hands on the ReadyNAS Pro!