How to run 65535 web servers on a single laptop

OK, so here's what crazy computer geeks come up with when they're bored of just sitting in the subway and staring out of the window.

Web servers usually run on port 80. TCP/UDP ports range from 1 to 65535 (port 0 is reserved). You can run multiple web servers on different ports at the same time... Do you think what I think?

Well, first you need a web server (duh). I decided to use lighttpd, as it's said to be small and memory-efficient (which sounded pretty important given what I was trying to do). Apache would probably not be a good choice here. Mind you, I have not done any benchmarks at all, I'm just guessing...

  $ apt-get install lighttpd

Then, I wrote a little shell script containing a loop, which invoked lighttpd on port 1, 2, 3, 4, ..., 65535. That's it ;)

  CONFFILE="server.document-root       = \"/var/www/\"
           index-file.names           = ( \"index.html\" )"
  for ((i = 1; i < 300; i = i + 1)) do
    echo "+++ Starting web server on port $i"
    echo $CONFFILE > $TMPDIR/lighttpd.conf
    echo "server.port = $i" >> $TMPDIR/lighttpd.conf
    /usr/sbin/lighttpd -f $TMPDIR/lighttpd.conf
    rm -f $TMPDIR/lighttpd.conf

I'm sure this can be optimized a lot, but it's sufficient for now, and it works.

You can test any of the web servers by running "wget http://localhost:3556/" (for example). You can kill them all with killall lighttpd. If you already run some other daemons on some ports, you cannot start a lighttpd on the same port, so you'll end up with fewer than 65535 servers.

In case you try this on your hardware, make sure you have lots of RAM and lots of swap. Don't run this on production hardware. Feel free to post your experiences in the comments.

Strange command line of the day

Stuff I didn't expect I'd had to type today:

  $ dpkg-repack dpkg-repack


Falling on your back for fun and profit -- human airbag device

Fun stuff I just stumbled over: a personal/human airbag from Japan, supposedly meant for elderly people who might fall and injure themselves.

Watch a video of the airbag in action on Youtube (no need for crappy Flash player, you can use youtube-dl for instance). Such a device could be a lot of fun I imagine; make it cheap enough and lots of people will buy it just for fun falling-on-your-back experiments :-)

Dear virus/worm/rootkit/botnet writer... time you write such a piece of malware, how about making it do something useful (instead of nefarious) for a change, say, have your botnet zombies become Tor exit nodes? kthxbye.

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