[VPN] lan to lan vpn over dsl!!?

Volker Tanger volker.tanger at discon.de
Thu Mar 27 03:40:55 EST 2003


Greetings!

On Wed, 26 Mar 2003 10:04:27 -0800 (PST) Jeremy Oliver
<jermwoliver at yahoo.com> wrote:

> I have a Nortel Contivity 1700 on my network for VPN tunnels.  I have
> some locations that I have dsl running into them.  Does anyone know
> how to create a lan to lan vpn connection over that dsl connection? 

No problem - except maybe for DSL with dynamic IP addresses (but there
are workarounds for that, too).


> We have tried to put a nortel 1010 vpn appliance on the dmz of the dsl
> router and have had no success yet.  Does anyone know the ports that
> need to be forwarded on the dsl router to get the nortels to talk?

Hehe - old trap to fall into. For IPSec it's not just UDP/500 (IKE), but
you'll need AH/ESP (IP protocols - not ports), too. Not all routers
support other IP protocols than ICMP, TCP and UDP. 

Another trap: VPN over NAT is quite nontrivial - best (read: usually impossible). 

Bye

Volker Tanger

IT-Security
discon gmbh
DeTeWe AG & Co. KG

Fon +49 30 6104-3307
Fax +49 30 6104-3435
http://www.detewe.de/




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