Raspberry Pi B

And here is it, after just six weeks of waiting!
As you can see on the image it is as long as a cigarette lighter.

Now I just have to find some free time to play with the Debian image and to install my little music station :)

Logging packets with iptables and ULOG

Imagine you have got the following iptables rule set:

:OUTPUT ACCEPT [119:14185]
-A INPUT -p tcp -m tcp –dport 22 -j ACCEPT
-A INPUT -p tcp -m tcp –dport 80 -j ACCEPT
-A INPUT -p tcp -m tcp –tcp-flags FIN,SYN,RST,ACK SYN -j DROP

This would allow all traffic from, on port 22 and 80. Other (TCP/IP) SYN packages (so on all the other connections) would be dropped.
Now you see, that your counter for the SYN DROP rule is increasing and you want to know what is rejected, but how?

The simple answer is ULOG – the netfilter userspace logging daemon.
In Debian you have got various implementations/variants of it, the local logging one (which I will use here, just called ulogd) and the -postgres, -mysql and -sqlite3 one (that are not the exact package names), with that you also can log everything to a (remote) database.
An special variant is the -pcap one, it will write the logs in the .pcap format, so you can analyze the full traffic.

So for our example it is enough to install the package:

apt-get install ulogd

And then add another rule BEFORE our SYN DROP:

-A INPUT -p tcp -m tcp –tcp-flags FIN,SYN,RST,ACK SYN -j ULOG
-A INPUT -p tcp -m tcp –tcp-flags FIN,SYN,RST,ACK SYN -j DROP

Now you will find in /var/log/ulog/syslogemu.log a log of all connections, which would be dropped, the log looks like this:

Aug 13 14:42:07 srv1 IN=eth0 OUT= MAC=00:0c:29:8c:2b:6c:00:d0:02:eb:e8:0a:08:00  SRC= DST=XXX.XXX.XXX.XXX LEN=40 TOS=00 PREC=0x00 TTL=54 ID=9566 PROTO=TCP SPT=57144 DPT=445 SEQ=2770468863 ACK=0 WINDOW=512 SYN URGP=0
Aug 13 14:45:29 srv1 IN=eth0 OUT= MAC=00:0c:29:8c:2b:6c:00:d0:02:eb:e8:0a:08:00  SRC= DST=XXX.XXX.XXX.XXX LEN=40 TOS=00 PREC=0x00 TTL=55 ID=13702 PROTO=TCP SPT=58528 DPT=445 SEQ=1217789951 ACK=0 WINDOW=512 SYN URGP=0

So you have got now the information about the full date, mac address (mostly it will be the one of your gateway), source and destination IP, source and destination port, length, protocol, etc.

You also could use it to log outgoing connections to port 80 and the IRC ports:

-A OUTPUT -p tcp -m tcp –dport 80 -j ULOG

-A OUTPUT -p tcp -m tcp –dport 6666:6669 -j ULOG

Whatever you want.

glusterfs Wheezy status

While many (german) IT magazines write about glusterfs since RedHat has taken it over, here is a short summarzy of the glusterfs Debian packaging status.

  • Debian stable/Squeeze delivers 3.0.5-1 and I just updated it on squeeze-backports to 3.2.7
  • Squeeze will come with 3.2.7, which is the latest release of the 3.2.x series. 3.3.0 was too new for me to upload it for Whezzy, also if it was released before Whezzy was frozen
  • You also could get 3.3.0 from experimental. 3.3.1 should be out soon and I will try to keep the packages up to date

If you are interested, I am still seeking for help!

Isla de Fuerteventura 2012

Just a few photos of my vacation on the Isla de Fuerteventura in july 2012 :) But travelling will be continued in 2012 to Belek in the Turkey on Oct+Nov!

OTRS updates

Debian Wheezy will come with otrs 3.1.7, I also backported one important upstream patch from 3.1.8 to it. Also you can get now 3.1.8+dfsg1-1 from experimental :)

With the 3.1.7 packaging I also migrated our otrs instance from 2.4.9 to 3.1.7 a few weeks ago, with some small problems:

  • We are using Apache as webserver for otrs, which requires the libapache2-reload-perl package. It is just a recommends, because if you run otrs on another webserver, it is not required. So this package was missing after the upgrade and Apache silently died. But having a look at the error.log mod_perl complains about the missing module.
  • We are using MySQL as database backend. With MySQL 5.5 Oracle changed the default storage engine from MyISAM to InnoDB, which is a good choice, but OTRS never used the ENGINE option in their installation and upgrade MySQL scripts. So if you upgrade an existing installation, some ALTER TABLE would fail, because of some FK fuck up between MyISAM and InnoDB tables. That was fixed with 3.1.5+dfsg1-2 by adding some “default storage engine” foo, but our remote MySQL cluster did not knew this option, yet, so I also had to patch out my patches on upgrading :(
    I am already interested in better fixes for the packaging!
  • Printing/Exporting tickets resulted in an “Internal server error”, fixed with 3.1.7+dfsg1-2 by adjusting the font paths. The Perl module has dropped the embedded font copies.

Now after five years of working with otrs 2.x in my company, all our agents accept the new 3.1 one and they are happy with it :-)

In the next weeks I also will check a backport of the 3.1.7 release for Squeeze.


Debian Wheezy status of fglrx-driver

After too much months without a working fglrx-driver for Wheezys Xserver 1.12 we have got now a fully working version!

What happened?

  • On the 14.05.2012 fglrx-driver was removed in favour of the xserver 1.12 upgrade
  • AMD decided to not publish their driver on an monthly base anymore :(
  • After some more user complaints AMD published the 12-6~beta driver with 1.12 xserver support, but it also removes support for “older” hardware (RadeonHD 2000-4000 series) and this release introduced the bug #675940 which made fglrx-driver completly unuseable on amd64 (crashing Xorg)
  • The 12-6 release also did not fix the crash bug and it was scheduled for something like october (if I remember correctly)
  • After some mail traffic with some AMD developers and another month waiting for an offical answer, AMD created a point release for Debian! Much thanks to AMD! So I have called it 12-6+point and it is working like a charm :)

Freeze exception for it is filled since > 10 days, we are now just waiting for an answer.

If you are missing support for the older RadeonHD series, Andreas (co-maint of fglrx-driver) just packaged the legacy driver, which is available in experimental.
Very much thanks to him, especially for all his very good fglrx-driver packaging work!