weblog d’un abbe

20061024

Ready to torrent Zod

Filed under: Fun — abbe @ 1934

Fedora Core 6 Zod is out. :-D

20061023

Conky

Filed under: Experiments, Hacking — abbe @ 2348

Conky

Conky, a cool lighweight system monitor is now available on Fedora Core 5. I’ve created an SRPM for it, which can be downloaded from http://wahjava.googlepages.com/conky-1.4.2-1.src.rpm . It is just another RPM which I built recently from scratch. And BtW, Fedora Core 6 is going to release tomorrow, so before you install it, why not try this package and comment on my rpmbuilding skills. ;-)

20061022

Google Mail from Germany

Filed under: Fun — abbe @ 0027

Google Mail from Deutschland

Google Mail (not Gmail) when accessed via a host in .de top-level domain.

20061019

Google felt sorry

Filed under: Personal — abbe @ 0008

Google felt sorry

Google felt sorry when I performed a Google search running on a Tor network. It seems that they’ve marked some IPv4 addresses as open proxies as Wikipedia marked.

20061013

So, you’re bored with @gmail.com gmail address

Filed under: Fun — abbe @ 0113

So, if you’re bored with @gmail.com gmail address, you can try a @googlemail.com domain name. Any mail sent to dc3434v4525aqw@googlemail.com will be delivered to mailstore as mail sent to dc3434v4525aqw@gmail.com. So you just have to advertise your googlemail.com address and you’re done. For more information, refer to Google Mail @ Wikipedia.

If you’re a Google Apps for Your Domain user…

Filed under: Research — abbe @ 0058

If you’re a Google Apps for Your Domain user then, there are 99% chances that you can’t interoperate with non-Google Jabber users. Why ? In Jabber technology (or precisely XMPP protocol), user of one server can IM to user of another server. e.g. The process that takes when wahjava@gmail.com wants to talk to wahjava@jabber.org is illustrated below:

  1. Client of wahjava@gmail.com sends message destined to wahjava@jabber.org to gmail.com jabber server i.e. talk.google.com server.
  2. talk.google.com then starts search for the jabber server handling jabber.org domain. It first performs a DNS query for SRV record of _xmpp-server._tcp.jabber.org domain name. It recieves 30 30 5269 jabber.org. (as of now). Now from this reply, it deduces that jabber.org is the jabber server handling jaber.org domain.
  3. It then sends this message to jabber.org jabber server.
  4. From jabber.org jabber server, the message gets delivered to wahjava@jabber.org.

Now if wahjava@jabber.org wants to talk to wahjava@jnoiyunrn027n47jlsu.com (a Google Apps for Your Domain user), then 99% of chances are that he can’t. Why ? Because there is no SRV record for XMPP service (i.e. SRV record corresponding to _xmpp-server._tcp.jnoiyunrn027n47jlsu.com) present in the domain nameserver of jnoiyunrn027n47jlsu.com domain. So if wahjava@jnoiyunrn027n47jlsu.com wants to enable Jabber service (provided by Google Apps for Your Domain) fully, he needs to add a SRV record in domain nameserver of jnoiyunrn027n47jlsu.com.

This is neither mentioned in any of Google’s FAQ for Google Apps for Your Domain. I found this after failing to inviting one of my friend (who is a Google Apps for Your Domain user) to a Jabber conference hosted at jabber.org. Thanks to users at jabber channel jdev in jabber.org server for explaining me how Jabber server discovery for a domain takes place (which prevented me from looking into its RFCs ;)).

If no matching SRV record is found then the IP address pointed by A record (and probably AAAA record too, though I’m not sure on this) of domain name is probed for Jabber service.

Anonymizing with The Onion Router

Filed under: Experiments — abbe @ 0000

Well last night, I tried tor (in combination with privoxy). As I’m on Fedora Core 5 AMD64 architecture and there is no prebuilt package available for my platform, so I downloaded its source tarball. Fortunately, it contains tor.spec (which is required for building RPMs). So I tried rpmbuilding on tor.spec but unfortunately that failed. So I hacked my own tor.spec file. In order to build tor using this file, make sure you’ve rpmdevtools package. rpmdevtools will assist you in building RPMs in non-superuser mode. If you’re using rpmdevtools, use rpmdev-setuptree to setup a build tree for you at ~/rpmbuild location. Now, download tor.spec file in {rpmbuild-root}/SPECS. And download tor-0.1.1.24.tar.gz from http://tor.eff.org/ into {rpmbuild-root}/SOURCES. Now start build with rpmbuild -bb {rpmbuild-root}/SPECS/tor.spec. This will result in tor*-0.1.1.24-1.{architecture}.rpm built in {rpmbuild-root}/RPMS/{architecture} directory. Now, since you’ve RPMs you know what to do ;-). After installing tor you can start it with sudo torctl start. You also need to install Privoxy. It is available as an rpm in FC5. For more details, refer to tor docs.

Why do we need an anonymizer ? Good question, I hope this page will answer you.

20061010

Wanna 1337Speak

Filed under: Fun — abbe @ 0048

Here is 1337Speak Guide.

#!/bin/sh
# The LEET-2-1337 converter
sed -e s/\[cC\]\[kK\]/X/g -e s/A/4/g -e s/B/8/g -e s/D/\|\)/g -e s/E/3/g -e s/F/\|=/g \
-e s/G/6/g -e s/H/\#/g -e s/I/\!/g -e s/J/_\|/g -e s/K/X/g -e s/L/1/g -e s/M/\|v\|/g \
-e s/N/\|\\\\\\\\\|/g -e s/O/0/g -e s/P/1\"/g -e s/Q/O_/g -e s/R/\|2/g -e s/S/5/g -e \
s/T/7/g -e s/U/\|_\|/g -e s\[V\[\\\\\\\\/\[g -e s\[W\[\|/\\\\\\\\\|\[g -e s/X/\>\</g

20061009

/ME became a FreeBSD port maintainer

Filed under: Personal — Tags: , , — abbe @ 1806

:D Yippee!! :D, finally my 2 (out of 4) ports are committed in the FreeBSD ports tree :). Actually, I submitted 4 ports, out of which only 2 are committed. The committed ports are x11/libxcb, and x11/xcb-proto.

20061006

Multicasting audio with VLC – II

Filed under: Experiments, Research — abbe @ 1247

Though I’ve no previous plans to release part-II. But unfortunately what I found after some packet sniffing, inspired me to post this next part. This part deals with the reality of multicasting. Multicasting is a good technique that can minimize the unnecessary traffic on the internet, but unfortunately it is not implemented properly (by ISPs, by network devices etc.) . First, read the following dump:

[abbe@chatteau-d-lf ~]$ vlc -I dummy --sout='#duplicate{dst=display,dst=std{access=rtp,\\
> mux=ts,dst=239.1.0.3:1234}}' http://ct4.fast-serv.com:9620 >&2 2>/dev/null &
[1] 24445
[abbe@chatteau-d-lf ~]$ ssh abbe@172.16.0.3
abbe@172.16.0.3's password:
Linux marseilles 2.6.15-27-amd64-generic #1 SMP PREEMPT Sat Sep 16 01:50:50 UTC 2006 x86_64 GNU/Linux

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.
You have mail.
Last login: Fri Oct  6 11:02:59 2006
abbe@marseilles:~$ sudo tcpdump -i eth0 ether multicast and dst port 1234
Password:
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
12:04:18.934508 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.075196 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.223828 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.368566 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.517352 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.666095 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.810695 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:19.955592 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:20.100319 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:20.248925 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:20.393607 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:20.542330 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316
12:04:20.686872 IP 172.16.0.2.32805 > 239.1.0.3.1234: UDP, length 1316

13 packets captured
27 packets received by filter
0 packets dropped by kernel
abbe@marseilles:~$ exit
logout
Connection to 172.16.0.3 closed.
[abbe@chatteau-d-lf ~]$ sudo /usr/sbin/tcpdump -i eth2 ether multicast and dst port 1234
Password:
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 96 bytes
12:05:53.730136 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:53.878769 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.023399 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.171926 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.316514 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.465112 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.609687 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.754349 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:54.902971 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:55.047641 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:55.196428 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316
12:05:55.341313 IP 172.16.0.2.32805 > 239.1.0.3.search-agent: UDP, length 1316

12 packets captured
24 packets received by filter
0 packets dropped by kernel

As you can see in the above dump, that the audio is being multicasted to a multicast ethernet address, but the network switch (in my case it is D-Link DES-1026G) is over (or under)-smart :-P. So it is not altering the destination address of the ethernet frame but instead broadcasting (not actually ethernet layer broadcast i.e. not destined for FF:FF:FF:FF:FF:FF MAC address) to all ethernet ports. Hence this is a virtual multicasting (or simulation of multicast ;-) ). So before going for any network device, make sure it supports multicasting properly (if you plan to multicast in future). And at last, I would like to thank Gautam for sharing his Late W. Richard Steven‘s UNP book, his knowledge, and that multiple unicast anecdote :-D with me.

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