Ubuntu

Karmic Koala
To add a permanent static route to a Karmic Koala system with one NIC, you need to edit the
/etc/network/interfaces file. The following section needs to be replaced:

# The primary network interface
auto eth0
#iface eth0 inet dhcp

Modify as follows:
# The primary network interface
auto eth0
iface eth0 inet dhcp
up route add -net 10.8.0.0 netmask 255.255.255.0 gw 192.168.0.3
down route del -net 10.8.0.0 netmask 255.255.255.0 gw 192.168.0.3

In some networks, e.g. the one of Helsinki University, computer's have to be registered in order to get connected. Upon registration the computer receives a name and an IP address. Every time it connects to the network, the DHCP server assigns it the same name and IP address. The DHCP server identifies computers based on the MAC address which is unique for every NIC. However, if you know the MAC address of a registered coputer, you can use it to connect to the network faking the MAC address. This is especially easy with Linux computers:
ifconfig eth0 down


I wanted to encrypt my Documents. My home folder is on a logical volume. So I made some space by removing another logical volume and creating a new one, which gets encrypted by cryptsetup. Here are the commands: