VPN mysteriously stopped working.

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I have been running a L2TP over IPSEC VPN for awhile now with no problems. For some reason it mysteriously stopped working at 6:45pm CST yesterday. Posted below is the debug log for crypto isakmp and ipsec. Attached is the debug output. 71.40.x.x is the ip address of remote office where the machines remoting in using windows vpn client. 72.5.x.x will equal where the cisco asa 5520 resides.

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Pravin Phadte Wed, 07/02/2008 - 07:21

Hi,

You need to check the extended authentication config (Xauth) and the Access Control List (ACL) or crypto ACL on both sides.

Regards,

Pravin

ggilbert Wed, 07/02/2008 - 07:36

According to the debugs, it says that the peer is not authenticated when doing username & password entry.

Jul 01 16:20:43 [IKEv1]: Group = DefaultRAGroup, IP = 71.40.x.x, peer is not authenticated by xauth - drop connection

What kind of authentication method are you using on the ASA for the L2TP clients? Is it local or RADIUS or no authentication.

I am doing local authentication.

Will it do LOCAL authenticationby default. I went to double checkand noticed that nder the tunnel-group general attributes there was no authentication methid specified. When I tried to specify it again using the authentication-server-group LOCAL it seems like it will not hold the command.

ggilbert Wed, 07/02/2008 - 08:26

You have to issue the command

sh run all tunnel-group DefaultRAGroup

You will see the authentication set to LOCAL at that point. Since it is default, it doesnt show up.

This is what i see when i run that command.

asa1# sh running-config tunnel-group DefaultRAGroup

tunnel-group DefaultRAGroup general-attributes

address-pool vpnpool

default-group-policy DefaultRAGroup

tunnel-group DefaultRAGroup ipsec-attributes

pre-shared-key ****

tunnel-group DefaultRAGroup ppp-attributes

no authentication chap

authentication ms-chap-v2

ggilbert Wed, 07/09/2008 - 06:55

Since it doesnt not show up, I believe the authentication method used is LOCAL at the moment.

sh run all tunnel-group DefaultRAGroup

The above command will give you all the information on the tunnel-group.

Gilbert

ggilbert Wed, 07/09/2008 - 06:57

Since your debug says that the peer is not authenticated by XAUTH - can you please collect the debugs for

deb aaa common 255 --this debug will give us more information as to why the authentication failed.

Thanks

Gilbert

pandooliza Thu, 07/10/2008 - 09:04

If you are running Windows and have installed the 07/08 security update KB951748 you might uninstall / reinstall the VPN and see if this resolves your problem. I had the same issue happen after the MS update and this fixed it for me.

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