apt-get not happy eyeball-ed ... ugly workaround

The tool 'apt-get' has no "happy eyeball" (RFC 6555) features. That means that a bad IPv6 connection can cause long delays: a plain "sudo apt-get update" took 18 minutes on my already uptodate machine. :-(

Cause: apt-get tries each server and it takes a long time to time-out:

0% [Connecting to security.ubuntu.com (2001:67c:1562::13)]    
0% [Connecting to security.ubuntu.com (2001:67c:1360:8c01::18)]
0% [Connecting to security.ubuntu.com (2001:67c:1562::15)]    

As long as apt-get has no happy eyeball built in, there is a ugly work around:

Create a file /etc/apt/apt.conf.d/99timeout with these contents

Acquire::http::Timeout "2";

Acquire::ftp::Timeout "2";

Now the time-out on non-reachable (IPv6) servers only takes two seconds.

Thanks to http://askubuntu.com/questions/141513/how-to-lower-wait-time-for-repository-updates

Install Git version of arp-scan on Ubuntu and Raspbian

If you need the newest arp-scan (for example because of it's uptodate MAC address list), here is how to install the Git version of arp-scan on Ubuntu and Raspberry's Raspbian (and probably Debian).

Disclaimer: no IPv6 involved.

Here's the set of commands:

sudo apt-get update && sudo apt-get upgrade
sudo apt-get install automake libpcap-dev

git clone https://github.com/royhills/arp-scan.git
cd arp-scan/

aclocal
autoheader
autoreconf -i
automake
autoconf
./configure 
make
sudo ./arp-scan --localnet --interface=wlan0

That should work: it should give the MAC addresses visible via interface wlan0. Change to eth0 if you're system is connected via eth0.

To install the new arp-scan unto your system:

sudo make install
sudo arp-scan --localnet --interface=wlan0

Check the version:

sander@flappie:~/git/arp-scan$ sudo ./arp-scan --version
arp-scan 1.9.2

Copyright (C) 2005-2013 Roy Hills, NTA Monitor Ltd.
arp-scan comes with NO WARRANTY to the extent permitted by law.
You may redistribute copies of arp-scan under the terms of the GNU
General Public License.
For more information about these matters, see the file named COPYING.

libpcap version 1.3.0
sander@flappie:~/git/arp-scan$

That's it. Happy arp-scanning!