Reinstalling Grub

If you ever need to reinstall your Grub loader, here is how to.

Boot with your First CD, or your live CD. Once you have the prompt go with this.

root (hd0,0)
setup (hd0)

You need to chage hd0 and the hd0,0 for anything your system needs.
hd0 is the first disk on the system
hd0,0 means the first partition of the first disk.

tcpdump (Linux Sniffer)

This is a great tool, a powerfull Linux sniffer, that lets you even sniff layer two packets.

All you need to do for using it is (as root) enter this command

tcpdump -i any -l
If you want to listen on any interface of you PC (could not work in Promiscuous mode) and put the output on the screen.

tcpdump -i eth0 -w file

This will instruc tcpdume to work only with etho (-i eth0) and to write to file the output for later analisys.

After capturing the file you can use Ethereal to graphic the results.