MSR5660 l2tp vpn problem with windows 11 negotiaton issue

irrelevant

 The L2TP connection attempt failed because the security layer could not negotiate compatible parameters with the remote computer.

1. check the configuration of router is correct

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 ip pool pool 10.1.1.2 10.1.1.10

 ip pool pool gateway 10.1.1.1

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interface Virtual-Template1

 ppp authentication-mode ms-chap-v2 domain l2tp

 remote address pool pool

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domain l2tp

 authentication ppp local

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local-user l2tpuser class network

 password cipher $c$3$HriZ/2PX1Are3l6Vu/nnqOErD02wFUPnQrTLu7A94O/2

 service-type ppp

 authorization-attribute user-role network-operator

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2.according to the error from Win 11, shows the negotiate issue...

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Modify the regedit of Win11 as follows:

1：Win+R and type regedit.exe

2：Find this path

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent

Edit-->New-->dword

Set  value of  AssumeUDPEncapsulationContextOnSendRule  2

 3：Find this path

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters

Edit-->New-->dword

Set  value of  ProhibitIPSec  1

Set  value of  AllowL2TPWeakCrypto  1

Start the relevant services:

1：This PC-->manage-->service

 IPsec Policy Agent和Routing and Remote Access 都改为自动，并且启动

Modify the vpn parameter,

Restart your PC to take effetc

Then succees to connect to L2VPN