problem with VPN L2TP client-Server USG 100

Dav975

Hi,

since a few weeks, i try to configure a VPN L2TP Client/Server. I followed the steps that were indicated in the documentation from Zyxell but when i want to connect to my VPN i have this message on windows :

"the L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the computer."

I checked all the options but I can't find where the problem comes from.

I have 4 VPNs site to site and they work well.

Can you help me?

Thank you,

Dav975

PS: Sorry for my english, i speak french and start to talk in english.

Zyxel_Charlie

Hello Dav975,
As your description, 
does L2TP server behind NAT router? Also, please double confirm the pre-share key is match.
Moreover, here is the SOP of configuration of USG and PC side from FAQ.
PC:
https://businessforum.zyxel.com/discussion/456/how-do-you-configure-l2tp-vpn-between-zywall-and-a-windows-7-laptop#latest
USG: Just ignore step 7.
https://businessforum.zyxel.com/discussion/618/how-to-use-the-vpn-setup-wizard-to-create-a-l2tp-vpn-on-the-zywall-usg#latest
Charlie

Dav975

Hello Charlie,

my VPN works. On the other hand, I have another problem.

I have two routers (which communicate with each other by another VPN) I have configured my outside VPN and my client on both (as you indicated above).

On one of them I always have internet, but on the other, I lose my connection. But my VPN works because I can join my servers.

Do you have an idea why i lose my internet connection?

Dav975

Zyxel_Charlie

Hello Dav975,
I want to confirm that do you mean if when "A" client access to internet via L2TP tunnel, another client"B" cannot, however, if when B client can access to internet, A client cannot?
Secondly, do both clients use the same account to login?
Thirdly, I want to check your configuration, please PM to me.
Charlie

Dav975

Hi Charlie,

I have a Client "A" and 2 USG 100 (USG "A" and USG "B") in 2 different building.

USG "A" has network address 192.168.1.0 and USG "B" has 192.168.2.0

Client "A" has network addres 192.168.1.0 at home.

When i connect Client "A" to USG "A" i have network and my VPN with USG "A". When i connect Client "A" to USG"B" i have my VPN with USG "B" but i don't have network.

Dav975

ok for network it's working.

Thank you!