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L2TP client behind ISA - 3.Nov.2006 1:29:28 AM

kwyap

Posts: 39
Joined: 8.Jun.2004
From: Malaysia
Status: offline

Hi,

My server was configured to allow outbound L2TP for secure nat client. Intermittenly, users failed to established the connection without any changes on the ISA. Some times restart the ISA would help to solve the problem, the worst case was reinstall the ISA. Did anyone of you faced the same problem as me and manage solve it? Sincerely thanks for any idea to solve my problem.

Post #: 1

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RE: L2TP client behind ISA - 3.Nov.2006 6:30:31 AM

spouseele

Posts: 12782
Joined: 1.Jun.2001
From: Belgium
Status: offline

Hi kwyap,

are you talking about L2TP or L2TP/IPSec? In the latter case, check out my article http://www.isaserver.org/articles/IPSec_Passthrough.html.

HTH,
Stefaan

(in reply to kwyap)

Post #: 2

RE: L2TP client behind ISA - 3.Nov.2006 12:04:04 PM

kwyap

Posts: 39
Joined: 8.Jun.2004
From: Malaysia
Status: offline

Thanks for your replied. The server was configured according to the guidence in VPN deployment kit downloaded from this website. It was working for some time only, impossible wrongly configured, am i right? Another issue was happened on my ISA, the DNS forwarding. I have a DNS server configured to hold internal domain zone and resolve external DNS. I was experienced failure in querying external domain name, i have checked on the forwarder tab, ensure the list of forwarders are alive. From the build-in monitoring tool, recursive querying was tested pass, but still not able to resolve the external DNS. After i work around, i remove all public DNS ip from the forwader list, left only the DNS ip located in the remote branch office, indeed the service has came back. Finally, i use the ISApolicy ImportExport script to backup all the settings and reinstall the ISA. Do you have these experience before?

.

(in reply to spouseele)

Post #: 3

RE: L2TP client behind ISA - 14.Nov.2006 3:35:44 PM

spouseele

Posts: 12782
Joined: 1.Jun.2001
From: Belgium
Status: offline

Hi kwyap,

nope, I never experienced such behavior on any of my ISA Server installations.

I would first start looking on low level problems such as the ISA interfaces and their settings, cabling, hub/switches/routers, etc..

HTH,
Stefaan

(in reply to kwyap)

Post #: 4

RE: L2TP client behind ISA - 15.Nov.2006 1:58:15 AM

kwyap

Posts: 39
Joined: 8.Jun.2004
From: Malaysia
Status: offline

Steefan,

Much appreciate for your replying. Do you know anywhere can raise this issue to microsoft? So far my manager has no instruction to upgrade the ISA to 2004 version.
Thank you.

(in reply to spouseele)

Post #: 5

RE: L2TP client behind ISA - 15.Nov.2006 2:32:35 PM