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
/Library/Preferences/com.apple.windowserver.plist
on the server side.

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

X:\
This entire drive will be backed up.
X:\Folder_name\
Files in this folder will be backed up.
X:\Folder_name\ /exclude
Files in this folder will be excluded.
X:\File_name.ext
This file will be backed up.
X:\File_name.ext /exclude
This file will be excluded.
SystemState
The System State will be backed up.
\\Server\Share\Folder\
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

Windows
Hex Editor XVI32

Mac OS X
HexEdit

Linux
Midnight Commander

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.

Mutt and nbSMTP

Not so long ago I installed in different locations a few PCs as servers.
I choose Ubuntu server edition 8.0.4 LTS (Long-Term Support) aka Hardy Heron, the latest LTS version available from Canonical.
I prefer the hard way, without the GUI. Sorry, I don't like Linux GUIs ;-)
That way I can control what is installed, and install just what is really useful for that particular machine, leaving precious resources to services that need them. There is also another advantage. Limiting possible security issues.
One of these servers, in particular, has to manage the nightly backup of another server, this time a Windows 2003, via rsync.
I created a bash script to do the job and scheduled it with crontab.
The script, during the process, creates a report that is saved as a zip archive when the work is finished.
I was wondering how could I get that file to check everything was fine, without remotely access the server.
The obvious response was. By e-mail.
I started hunting for information in search for the most elegant solution with the minimum impact on the system.

What I found, and I picked, to achieve my goal, are these two little gems.

Mutt "a small but very powerful text-based mail client for Unix operating systems" and No Brainer SMTP nbSMTP "a simple MTA to send your mails to another mail server via SMTP".

First step. Retrieve and install the two packages. In Ubunto the apt-get command is aimed at that.

sudo apt-get install mutt
sudo apt-get install nbsmtp

I created a user specific .muttrc containing these lines

# No need to keep copy of the outgoing messages
set copy=no
# Some changes to the message headers
set hdrs=yes
my_hdr From: Me the sender <me@mydomain.com>
# How to invoke nbsmtp
set sendmail="/usr/bin/nbsmtp -f me@mydomain.com -d mydomain.com -h my_isp_smtp_server.com"

and to complete the work, at the end of the bash script that is supposed to make the backup, I've added the line in charge of sending the message

mutt -s "Backup report" -a report.zip me@mydomain.com < messagebody.txt

"Backup report" - is the subject of the message (option -s)
report.zip - is the attachment (option -a)
me@mydomain.com - is the recipient
messagebody.txt - is the main body of the e-mail (read message from the file messagebody.txt)

The file messagebody.txt could be anything you want to insert as the body of the message being sent.

Last but not least :-) I've also inserted this line into crontab file

MAILTO=""

to avoid error warning in log file
nbSMTP does not support the -o arguments from sendmail, ignoring them

because every time a croned job is executed mail is sent to the owner of the crontab

Windows XP Display Properties

Generally due to a virus attack, sometimes some pages under Display Properties are no longer available.
Run Regedit and search for
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\

Remove keys, if they are present

NoDispAppearancePage
NoDispBackgroundPage
NoDispScrSavPage
NoDispSettingsPage

Now the Display Properties should be OK.

If, also the Task Manager is grayed out, there is a chance to find this key too

DisableTaskMgr

that must be removed.

How to change default umask Leopard, Tiger and Panther

If, for some reason, you need to change the default umask (022) in Mac OS X Leopard the following article helps you in achieving that goal.

The article refers to Leopard server.
I tried it on Leopard workstation and seems to work just fine too.

The same can be done for Mac OS X Tiger in Terminal

sudo defaults write -g NSUmask -int value

as stated in Command Line 10.4 2nd edition manual

The above example applies on Mac OS X Panther too.

*** BE CAREFUL ***
These changes could possibly have nasty consequences on the normal behaviour of the system.