IPSec and Nat-traversal

[Dom Coppola]

Hello,

I know that I should be posting this in an XP newsgroup, but I could
not find anything that had to do with networking so I figure this might
be the best place, so I apologize if this post isn't meant for this group.

Here is my problem. I am currently trying to create a VPN tunnel to a
VPN appliance using the tools available to me on Windows XP. I have
installed Service Pack 2 because there was improvements made to IPSEc
and NAT-t. However, I have been unable to make a connection to my VPN
box when I am sitting behind my router. If I connect directly to the
internet and create a connection, which by the way is using "L2TP IPSec
VPN" it works like a charm, however once I get behind my router there is
nothing but issues.

I have read what seems like a million different opinions on this and
none have worked, and the only thing I am clear on is why it is
happening. That part makes total sense. But I am not sure as to how I am
going to get this to work. I normally would use third party software to
connect to VPN boxes, but in this case I felt that the installed Windows
Xp utility would do the job just fine as long as the VPN appliance
supported L2TP, which in this case it does.

Could anyone walk me through this as I might be doing something wrong
once I am behind the router, is there maybe a step that I missed. Any
help would be greatly appreciated.


Thanks In Advance

 

[Guest]

Hi Dom,

you are perfectly right. When I found the kb Q818043 I thought it would
solve the problem of clients laying behind e NAT device. I though it was
windows the responsible of applying NAT-T encapsulation and I thought there
were options to tell the IPSec service that NAT-T should be done.
I'm quite confused about the device which should do ESP or AH encapsulation.
I was convinced that the Windows IPsec engine would do it, otherwise, what
kind of NAT-T support has the Q818043 added ?

I'm sorry but I'm too looking for answers to these issues.