win7 l2tp配置

https://www.synology.com/zh-cn/knowledgebase/DSM/tutorial/Application/How_to_connect_to_Synology_s_VPN_Server_using_a_Windows_PC_or_Mac

修改注册表

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RasMan\Parameters]
"ProhibitIpSec"=dword:00000000

添加注册表

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent]
"AssumeUDPEncapsulationContextOnSendRule"=dword:00000002

调整并开启3个服务

Remote Access Auto Connection Manager
Remote Access Connection Manager
Secure Socket Tunneling Protocol Service