Ubuntu, how to regenerate OpenSSH host keys

First, change directory to /etc/ssh

cd /etc/ssh

now, remove the old rsa and dsa keys files

sudo rm ssh_host_*

Generate new keys

sudo dpkg-reconfigure openssh-server

If you wanto to be 100% sure that the server you are connecting to is the one it claims to be, take note of the RSA and DSA fingerprint

sudo ssh-keygen -l -f ssh_host_rsa_key
sudo ssh-keygen -l -f ssh_host_dsa_key

to check against the fingerprint displayed next time you are going to connect.

Last, update your known_hosts file

~/.ssh/known_hosts

removing the line that contains the old reference, otherwise you'll get the following message

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!

Stop VMware Fusion to automatically map shared folders

If your Windows XP virtual machine under VMware Fusion (v2) insist to map the shared folder as unit Z: and creates a shortcut on the desktop you must edit the relative .vmx file.

Usually this file is hidden under the following directory

/Users/YourUserName/Documents/Virtual Machines/YourWinVMName.vmwarevm

Find and change to FALSE the following keys

hgfs.mapRootShare = "TRUE"
hgfs.linkRootShare = "TRUE"

The first one is in charge to map the share without your intervention, so that when you open up My Computer you magically find a Z: unit.
The last one tells Fusion to create a shortcut on the desktop.