VPN L2TP Connection not responding

ame...@gmail.com

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Dec 12, 2005, 12:21:21 AM12/12/05

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Hello,

L2TP does not respond when i try to connect over the internet. PPTP
works perfectly.

Here are the configurations:

Server:

Windows Server 2003 (SP1)
L2TP w/ IPSEC pre-shared key configured
Server is behind a D-Link DI-784 Router with IPSEC passtrought enabled.
Also port 500/1701(udp) are forwared to the server.

Remote station:
Windows XP pro (SP2)
VPN connection configured with the pre-shared key.

I also tried to but the vpn server in the DMZ but still no anwser.

For contact: ame...@gmail.com

Crina Li

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Dec 12, 2005, 10:40:44 PM12/12/05

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Hi Amensi,

Thank you for posting in SBS newsgroup.

From the description, I understand that you have configured the Windows
Server as a L2TP VPN server, however, you have problems establishing a L2TP
VPN connection. If I have misunderstood your concern, please do not
hesitate to let me know.

To narrow down the problem, would you please help me collect the following
information?

1. Are you using Windows server 2003 or SBS 2003?
2. What's the exact problem symptom?
3. Is there any related error in the event viewer?
4. Do you have ISA installed?

Please check out the following Knowledge Base article and see if it helps:

247231 Event ID 20111, Error 792 or Error 781 When Establishing an
L2TP/IPSec Connection
http://support.microsoft.com/?id=247231

Regarding the configuration of L2TP VPN, please also refer to the following
documents:

Step-by-Step Guide for Setting Up Network Quarantine and Remote Access
Certificate Provisioning in a Test Lab
http://www.microsoft.com/downloads/details.aspx?FamilyID=fe902704-52dd-4bbe-
8a75-f8fbb76cd28a&DisplayLang=en

240262 How to configure an L2TP/IPSec connection by using Preshared Key
http://support.microsoft.com/?id=240262

259335 Basic L2TP/IPSec troubleshooting in Windows 2000
http://support.microsoft.com/?id=259335

I am appreciated your time and look forward to hearing from you.

Best regards,

Crina Li (MSFT)

Microsoft CSS Online Newsgroup Support

Get Secure! - www.microsoft.com/security

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--------------------
| From: ame...@gmail.com
| Newsgroups: microsoft.public.windows.server.sbs
| Subject: VPN L2TP Connection not responding
| Date: 11 Dec 2005 21:21:21 -0800
| Organization: http://groups.google.com

SunTzu

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Dec 13, 2005, 1:08:49 PM12/13/05

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Hi,

I am using Windows Server 2003 Enterprise (not SBS)

Symptoms, Whenever i try to connect from the internet to my vpn using
PPTP, eveything is perfect, connections, dns and dhcp are working
properly. Whenever i try to do the same with L2TP, serve is not
responding. There are no errors in the event viewer. My server is
behind a D-Link Di-784 Router as i precendently describe. There are no
ISA server present.

Maurice Bishop

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Dec 13, 2005, 6:08:32 PM12/13/05

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Amensi

Greetings

Disable IPSEC.

IPSEC will not traverse NAT, no matter what your router says.

Maurice

<ame...@gmail.com> wrote in message
news:1134364881....@z14g2000cwz.googlegroups.com...

Crina Li

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Dec 13, 2005, 9:03:52 PM12/13/05

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Hi Amensi,

Thanks for your reply.

According to my research, it appears that the XP client cannot establish
the connection if the NAT router does not open the following required ports
and protocols for L2TP/IPSec NAT-T connections.

- L2TP - User Datagram Protocol (UDP) 500, UDP 1701
- NAT-T - UDP 4500
- ESP - Internet Protocol (IP) protocol 50

Please make sure that all of the ports and protocols are opened.

In addition, based on the information you provided, this should be an issue
regarding Windows Server 2003. For more information, please post it to
Microsoft.public.windows.server.general newsgroup for better support. The
reason why we recommend posting appropriately is you will get the most
qualified pool of respondents, and other partners who read the newsgroups
regularly can either share their knowledge or learn from your interaction
with us.

More information:

818043 L2TP/IPsec NAT-T update for Windows XP and Windows 2000
http://support.microsoft.com/?id=818043

Thanks for your understanding.

Best regards,

Crina Li (MSFT)

Get Secure! - www.microsoft.com/security

=====================================================