Set up FreeNX with LXDE on Arch Linux

1. install poptop server

pacman -S pptpd

2. edit the configuration file

vim /etc/pptpd.conf
--

option /etc/ppp/pptpd-options
localip 172.16.1.254
remoteip 172.16.1.1-253

localip is ip of pptp server
remoteip is the ip range which vpn client will get from

3. edit /etc/ppp/pptpd-options

name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
proxyarp
lock
nobsdcomp
novj
novjccomp
nologfd
ms-dns 168.95.1.1
ms-dns 168.95.192.1

require-mppe-128 enables encryption
ms-dns is dns server address

4. start pptp server

/etc/rc.d/pptpd start

5. add username and password to /etc/ppp/chap-secrets for ppp authentication

<username>     pptpd     <password>   *

6. make your iphone be a pptp client, General -> Network -> VPN -> Add a VPN -> PPTP
then fill all required fields and save

7. turn on VPN then you'll see the timer start timing

Boot a Virtual Machine from command and Control it through Remote Desktop Protocol on Ubuntu

1. we will need VBoxHeadless command to run virtual machine in background, free version of virtualbox in ubuntu repository doesn't have it. so we need to install official version
from http://www.virtualbox.org/wiki/Linux_Downloads

complie VirtualBox Modules

sudo /etc/init.d/vboxdrv setup

2. set up your virtual machine completely through GUI, Applications -> System Tools -> Sun xVM VirtualBox. if you can't find the icon, just relog desktop environment after installed

change Settings -> Remote Display -> Enable VRDP Server
Authentication Method = Null

its unsafe but we will set something for security on windows later

3. command-line usage

start a virtual machine

VBoxHeadless -startvm "name"
or
VBoxHeadless -startvm "uuid"

poweroff a virtual machine

VBoxManage controlvm "name" acpipowerbutton

show info about a running virtual machine

VBoxManage showvminfo "name"

4. your login screen of guest windows has a shutdown button, it means anyone who connect to the right port can shutdown your machine. we have to hide it by changing the registry below

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system\shutdownwithoutlogon -> 0

5. the last thing I must remind is remember to logout / switch user then windows will back to login screen. if you are afraid of forgetting to do so, try set screensaver with password protection. nobody can kick you if you are connecting and occupying the port.