No time for blogging

By the way, I was very busy with moving to another flat and after that we travelled to Erlangen, where I planned to (re)start writing my thesis. Thus I had no time for blogging.

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ip_conntrack table full

Since I had some spare time, I checked the Mora dormitory network again, and I’ve found this:
tracked IP connections - daily graph

Some remarks:

  • There is one or more infected machines on the network: see the high amount of SYN_SENT connections. I suppose it was a single machine being turned off between 23:00 and 7:30.
  • Another suspicious thing: the high amount of TIME_WAIT connections. The timeout is 120 secs, that is the average 714 means almost 6 connections are closed each second. Given that it is now summer and only a few machines are in the dormitory, this is an obvious irregularity (nice expression 😉
  • The number of ESTABLISHED connections is also high.

My conclusions: there is an infected machine, and there is a large amount of file sharing there. You don’t have to be Sherlock Holmes to find it out in a dormitory. I also think some applications just drop the connection, since the number of the ESTABLISHED entries does not correspond to the active connections shown for example by iptraf. Grrr…

So I decreased the timeout for SYN_SENT (from 120s to 60s), TIME_WAIT (also 120s to 60s) and ESTABLISHED (from 432000s/5days to 43200/12hrs).

By the way, I already have found ideas, how to tweak the router settings such that the network won’t be flooded (up to unsuability):

By the way, perhaps I should test Zabbix to replace Munin. There are debian packages of it. Althouh only the MySQL backend, and not the PostgreSQL. Why??? That was one (the) blocker for me to try Cacti, but fortunately Zabbix can use PostgreSQL as well.

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DRM is bad

My opinion is that DRM is bad. Very bad. Some more stuff is here: and here:
defecitve by design

I cannot understand this world. By trying to enforce our will, and seeking for our good, the world is converging to a local optimum, as it happens often with greedy algorithms. DRM means extra cost and effor to the content provider, to the manufacturer and mostly to the end user. And what is the profit? The entertainment industry will earn more. But this means only transferring the money from people (ca. 5 billion) to a small minority (1 million?). And what are we paying for??? Yes, it’s an effort to create a content. But what is the difference if I look at it once, or if I make a copy for myself, look at it again, or I share it with friends, and week look at it together. The effort needed to create the content is always the same.

My favourite example is from the bible, just think about it:
Then he took the seven loaves and the fish, and when he had given thanks, he broke them and gave them to the disciples, and they in turn to the people. They all ate and were satisfied. Afterward the disciples picked up seven basketfuls of broken pieces that were left over.
Matthew 15:36-37

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