Wednesday, April 25, 2012

NNTPgrab: Another IPv6-enabled newsgroup downloader

I just discovered another IPv6 enabled newsgroup downloader: NNTPgrab. It has a built-in search function. Quite handy.

NNTPgrab runs on Mac OS X, Linux and Windows. Homepage is

Installation on Ubuntu was easy, thanks to the PPA provided by Erik van Pienbroek:

sudo add-apt-repository ppa:openftd/ppa
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install nntpgrab

Then start up NNTPgrab by typing "nntpgrab_gui". In the popup-window, select "Start standalone" in the right bottom corner. That will start the server and the GUI.

Alternatively you can start a separate server and GUI:


In the GUI you can add your newsserver. I used the following free newsservers:

The downloads go quite well, although they seem to stay in ~/NNTPGrab/Temp and are not moved to ~/NNTPGrab/Downloads

PS: the NNTPgrab config file is


EDIT: there is a better GUI. Install it with:

        sudo apt-get install nntpgrab-gui-qt

Then start with the GUI with "nntpgrab_gui_qt" (so: underscores, not dashes), This Qt-GUI looks better, and can actually connect to remote nntpgrab-servers.

Happy downloading!

Tuesday, April 24, 2012

T-Mobile US provides IPv6 using unlocked UMTS Nexus & Galaxy Nexus Phones

Very interesting: T-Mobile US provides IPv6 using unlocked UMTS Nexus & Galaxy Nexus Phones

You have to set up a IPv6 (-only?) APN. 

Most interesting part: "T-Mobile's IPv6 service is an IPv6-only service that uses NAT64 and DNS64 in the network to connect IPv6 mobile users with IPv4 content. ". So your phone *only* uses IPv6 (no IPv4/IPv6 dual stack), and T-Mobile converts that to IPv4 when needed.

This method is probably in line with the current APN, which does NAT44. Going to NAT64 is then probably a small step, and easier than providing dual stack. 

Sunday, April 22, 2012

Great IPv6 article "Measuring Dual Stack Quality" by the web browser

Wow! An ex-colleague of mine (Max) sent me a great article/presentation "Analysing Dual Stack Behaviour and IPv6 Quality" written by Geoff Huston & George Michaelson of APNIC. The presentation is here:

The article is about dual-stack (both IPv4 and IPv6) situations, and how to handle them in the best way. As expected, the article concludes that a lot of IPv6 connections are not functioning at all. The problem can be on your local system or network, but also at the other end, or somewhere in between. If you would first use IPv6, wait for a time-out, and then use IPv4, your browsing experience would be horribly slow. That should be avoided.

The solution is this:
  • the web browser should both query for A (IPv4) and AAAA (IPv6) addresses. This should happen in parallel
  • then the web browser should measure both and in parallel the speed of the IPv4 and the IPv6 connection using a SYN packet
  • based on that measurement, the web browser should use the fastest connection
So this completely according to the old Dutch engineering's saying "meten is weten, gissen is missen" ;-)

What is unclear to me, is if/how the current browsers have already implemented the above. I used wireshark with Chromium 18.0.1025.151 (Developer Build 130497 Linux) on Ubuntu 11.10, and I did see the A and AAAA lookups, but then only a SYN over IPv6, not over IPv4 (for website which has both a IPv4 and IPv6 address + connectivity).

Some interesting conclusions from the article:

A lot of IPv6 connections are not working: about 40%!

The IPv6 failure depends on the IPv6 technology used: unicast/native is quite good, Teredo/Miredo is quite bad:

The articles also compares the speed of different IPv6 technologies to IPv4: Unicast and 6to4 are faster than IPv4 (!), Teredo/Miredo is slower:

All in all a great article! Kudo's to Geoff Huston & George Michaelson.