L2TP/IPSec VPN with IPSec disabled on WindowsXP/MacOSX/iTouch/iPhone/iPad

Sat, 02/04/2012 - 17:57 — administrator

As we know, L2TP doesn't encrypt the data itself, it use IPSec to encrypt the data.
So, why should we disable IPSec?
Mainly, there are two reasons for disable IPSec for L2TP/IPSec VPN:

1. Some Wireless Routers don't support L2TP/IPSec well. For example, some Mac OSX clients use a random high port as source port which will cause some problem. Disable IPSec may help.
2. If you are using unstable networks (for example : mobile phone network) and need to connect VPN over and over again, disable IPSec will save your time as the connection time will be shorter.

So, How to disable IPSec?
Important: Disable IPSec will disable the data encryption. Don't do this if you care about data security.

Windows XP Add one value below to Registry table:

Mac OS X / iTouch / iPhone / iPad Execute command below, write config value to config file.

echo -e "plugin L2TP.ppp\nl2tpnoipsec" > /etc/ppp/options

For detail steps:

Windows XP
Windows XP disable IPSec
  1. Download DisableIPSec.reg file.
  2. Double click DisableIPSec.reg to import the file to System Registry
  3. Restart your computer to take it effect
Mac OS X disable IPSec
  1. Navigate to /Applications/Utilities and click on Terminal to start the Command Shell.
  2. type echo -e "plugin L2TP.ppp\nl2tpnoipsec" > /etc/ppp/options in the Terminal and press Enter.
  3. type your user password and press Enter.

ps: You need to jailbreak your iTouch / iPhone / iPad first to disable IPSec.