5.18 NAT背后的L2TP/IPSec VPN Client工作异常
Q:
系统是XP SP2，位于NAT背后，当通过L2TP/IPSec VPN Client访问NAT外侧的VPN Server时出现异常。
A:
参看如下两篇KB:
The default behavior of IPsec NAT traversal (NAT-T) is changed in Windows XP Service Pack 2 http://support.microsoft.com/kb/885407
IPSec NAT-T is not recommended for Windows Server 2003 computers that are behind network address translators http://support.microsoft.com/kb/885348
此时应该仍可正常使用PPTP VPN。