sabato 16 maggio 2009

VNC screen scrambled

Many Apple servers out there are headless. That is particularly true for the ones before the advent of the Xserve with Intel processor.
And quite often, servers are managed remotely using software like the multitude of VNC server (GPL) or Apple Remote Desktop (commercial).

I personally choose Vine Server OSX Vnc to control a couple of Xserve. One with Panther server and the other one with Tiger server. This program has the advantage to handle international keyboard layout over the VNC server self contained in Tiger which can't.

I think I played around with Monitor Preferences because at some point logging into the VNC server presented a screen like this.

For some times I ended up quitting the VNC client and relaunching it again to get a comprehensible image. But that was very annoying.

So I did some internet searches and I found the solution to the problem removing the file
on the server side.

domenica 3 maggio 2009

NT Backup and .bks file (reloaded)

The Windows program NT Backup can use a file with the extension .bks that contains the list of files or group of files to be saved.
As a matter of fact you can also use this file to exclude some files you don't want to be included into the backup set.

The syntax of the .bks file is as follows

This entire drive will be backed up.
Files in this folder will be backed up.
X:\Folder_name\ /exclude
Files in this folder will be excluded.
This file will be backed up.
X:\File_name.ext /exclude
This file will be excluded.
The System State will be backed up.
These network files will be backed up.

This file is normally created and managed by the program itself and it seems to be the only way to obtain a properly formatted .bks.

In fact, the .bks file is a "special" UNICODE file without the Unicode header (0xFFFE).
If you manually edit this file i.e. with NOTEPAD, the standard text editor included since the first version of Windows, and save it as a Unicode you are ruined. The scheduled backup job stop working.
It is very handy indeed to be able to manage that file as you like with your favourite text editor.
As long as you do that you need to strip the first two bytes (0xFFFE) off the .bks.

A simple way is to use a hexadecimal file editor.

Below you'll find some links to a few Hex Editor programs

Hex Editor XVI32

Mac OS X

Midnight Commander

sabato 24 gennaio 2009

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


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

Someone could be eavesdropping on you right now (man-in-the-middle attack)!

venerdì 16 gennaio 2009

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.