blog.crox.net

• http://ipv6-test.com/ (also has a speed test, shows your MAC address when available)


• http://test-ipv6.com/ (provides detailed technical info and "readiness score")


• http://whatismyv6.com/ (IPv4 only, IPv6 only)


• http://www.whatismyipv6.net/ (provides traceroute and ping, also suports IPv4)

According to the Wikipedia IPv6 article, Privacy extensions are, except for the Windows platform and Mac OS X since 10.7 as well as iOS since version 4.3, not enabled by default.

In theory, one can enable the IPv6 Privacy Extensions on all interfaces at once using sysctl like this:

sudo sysctl net.ipv6.conf.all.use_tempaddr=2

However, this currently doesn't work as expected, so I'm using this one-liner in /etc/rc.local:

for IF in `/bin/ls /proc/sys/net/ipv6/conf/*/use_tempaddr` ; do echo 2 > $IF ; done

This also sets "use_tempaddr" for "default", which means it should also apply to interfaces added to the system afterwards.

A simple check to verify that the new configuration is working: ipv6-test.com will print your MAC address when available...

See also: Linux Kernel Bug 11655

Les instructions pour Linux fournies sur le site officiel ne fonctionnent pas pour moi (Maverick / Ubuntu 10.10 desktop amd64).

Il semble qu'il ne soit toujours pas possible d'importer des fichiers sauvegardés dans une version 32 bit de VaudTax avec la version 64 bits, et vice-versa (crash de VaudTax avec une erreur cryptique [1]). Deux options, soit recommencer sa déclaration sans importer les données de l'année précédente, soit faire tourner VaudTax avec une JVM 32-bits ([2]). Pour l'instant j'ai toujours opté pour la deuxième variante. Jusqu'à l'année passée (VaudTax2009), on pouvait télécharger une version incluant une JVM (32-bits), cette option n'est plus disponible mais il est toujours possible d'arriver au même résultat :

1ère étape, avant de commencer le processus d'installation :

$ sudo update-alternatives --config java
There are 3 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                       Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-6-openjdk/jre/bin/java    1061      auto mode
  1            /usr/lib/jvm/ia32-java-6-sun/jre/bin/java   63        manual mode
  2            /usr/lib/jvm/java-6-openjdk/jre/bin/java    1061      manual mode
  3            /usr/lib/jvm/java-6-sun/jre/bin/java        63        manual mode

Press enter to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/lib/jvm/ia32-java-6-sun/jre/bin/java to provide /usr/bin/java (java) in manual mode.

(si l'option JVM 32-bits n'apparaît pas, il faut d'abord installer le paquet ia32-sun-java6-bin)

Une fois VaudTax installé, il faut télécharger et décompacter xulrunner :

$ cd $HOME/VaudTax2010
$ wget http://releases.mozilla.org/pub/mozilla.org/xulrunner/releases/1.9.2.16/runtimes/xulrunner-1.9.2.16.en-US.linux-i686.tar.bz2
$ tar -xpf xulrunner-*

Finalement, il faut encore modifier le fichier VaudTax2010 en ajoutant ces deux lignes juste après `VM_SEARCH_PATH="$PATH"' :

export MOZILLA_FIVE_HOME=$HOME/VaudTax2010/xulrunner
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${MOZILLA_FIVE_HOME}

Note : une fois VaudTax2010 installé, on peut exécuter à nouveau "sudo update-alternatives --config java" pour rétablir la configuration initiale - les paramètres sont en effet enregistrés dans le fichier VaudTax2010.lax


[1]

The program 'SWT' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial 5455 error_code 161 request_code 149 minor_code 7)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

[2] la troisième variante serait d'étudier le format de fichier produit par chacune des versions pour créer un outil de conversion

Let's say you want some output to be echoed to the console but also to be passed to a pipe. Specifically, in my case I wanted a message to be displayed to the user and also to be sent to syslog. You could of course just print it twice, but in some cases it's not possible, or it makes it more complicated than it should be.

There is a simple solution with tee:

echo "a test" | tee >(logger)

tcpdump and wireshark are the tools that usually come to mind when you have to capture network traffic. But in some situations where you have to record a large amount of data and you want to avoid losing packets, tcpdump has some limitations. When I was hit myself by the tcpdump packet loss problem, I quickly found out that I was not alone and that a number of people had already researched the topic and/or provided alternatives.*

In particular, I found two different tools to perform the task: Corey Satten's gulp (http://corey.elsewhere.org/gulp/) and lindump from HP Labs (http://tesla.hpl.hp.com/opensource/)

I also found two interesting papers about capturing high volumes of traffic: http://www.usenix.org/events/fast09/tech/full_papers/anderson/anderson_html/ and http://docs.di.fc.ul.pt/jspui/bitstream/10455/3299/1/thesis-nhenriqu.pdf (the second quotes the first one among others, and also contains useful info to optimally spread the load among different cores)

After some tests I quickly became a happy gulp user, and thanks to the software being open source I was able to add features to it that I missed from the latest tcpdump versions:

-n - allows to change the default filename template
-t - allows to add a timestamp to the filename
-G - rotate pcap file every n seconds
-F - allows to skip the check for an ethernet interface

I've sent a patch to Corey Satten, who intends to setup a repository to hold the various contributions he gets for gulp. In the meanwhile, you can find my changes in the attached file (02-gulp-ntGF.patch.gz). For your convenience and for completeness, I also provide here the patch from Guy Harris that fixes issues on 64 bit systems (see http://seclists.org/wireshark/2009/Oct/105, apply that one first).



* other people have reported a performance drop with libpcap version 1.0 compared to previous builds, see http://thread.gmane.org/gmane.network.tcpdump.devel/4629 or http://seclists.org/tcpdump/2010/q3/index.html#11