I believe Cisco's preferred method for this is through specific products
designed for VPN router to router communication
700, 800, 1600 and 1700 series.
In theory, an IPSec compliant box on your side should be able to talk to an
IPSec compliant box on the Corporate side. These things are not necessarily
so at this time.
The idea being that if you had a Cisco router with the firewall and IPSec
feature set, you could configure the router such that your VPN traffic would
go to the designated tunnel device at corporate, and the rest of your
internet traffic would go as it pleased. I did a lab on this a ways back and
published the generic configs to show how the principal works.
Otherwise, the way I have seen most designs, someone with a DSL connection
installs client VPN software on their machine, using that means to create
the secure tunnels. This is actually one of the security concerns, in that
the presence of this shim software does nothing to ensure that the machine
itself is secure.
In your configuration, the preferred manner would be to run the VPN tunnel
from edge to edge, and leave the PC client untouched. There are any number
of known issues with PC shims anyway.
I look forward to hearing what TAC says. Secure VPN client to a Pix?
Chuck
-----Original Message-----
From: Greg Smythe [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, May 30, 2000 3:12 PM
To: Chuck Larrieu; [EMAIL PROTECTED]
Subject: Re: VPN through NAT
I'm trying to VPN from my Home, through a NAT router, over the internet, and
into a VPN server on the corporate network:
This is what I have:
PC -------| <private IP addresses>
|
nat rtr
| <internet ip address>
internet
|
VPN server
|
| <private IP addresses>
If that's not readable: PC <Private IP addresses> --NAT
Router--Internet--VPN Server (NT)--Corp LAN
On my NAT router I see it trying to connect but something not passing over
the router correctly.
As a last resort I have just opened a case with the TAC (I decided to try on
here first to see if I could get a fast response <smile>). I'll let the list
know what they say. My case was just dispatched to a tech.
Greg
----- Original Message -----
From: "Chuck Larrieu" <[EMAIL PROTECTED]>
To: "Greg Smythe" <[EMAIL PROTECTED]>; "Ric Messier"
<[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Tuesday, May 30, 2000 2:56 PM
Subject: RE: VPN through NAT
To bring this back into the realm of education and enlightenment, let's look
at the design issue.
You are going VPN, ie secure tunnel from where to where?
Home----internet-----firewall-----inside_network is the "standard"
configuration, with you the user wanting to work from home for some perverse
reason. ;->
But in the case you state, it would appear that you the user are in the
office, and want to VPN to some other place?
Corp_net-----internet-----some_other_place
Now as a matter of security policy, does corp_net want to allow people on
the inside to connect snug and secure and private to some unknown place on
the outside... say a competitor's network, where you will then transfer
company secrets?
As a matter of policy, companies might not want traffic whose contents
cannot be inspected to be passing through their firewalls.
Yes there are all in one products, such as the Checkpoint VPN firewall,
which operate in such a manner.
Inside----checkpoint-(VPN/NAT----tunnel/non-tunnel)-internet-----someplace_e
lse
But as a matter of design, NAT not withstanding, it is in my opinion at
least, not a good idea to permit unrestricted VPNs from inside to outside.
If there are extranets to be considered, then one should design a routing
situation in which those who need to connect to particular VPN devices would
be routed to particular pieces of equipment, from which the extranet VPN
would be established.
Inside-----firewall---internet
|-----VPN/extranet----business_partner
Hey, guys, have I muddied this up enough? :->
Chuck
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Greg
Smythe
Sent: Tuesday, May 30, 2000 2:13 PM
To: Ric Messier; [EMAIL PROTECTED]
Subject: Re: VPN through NAT
So I can't make a VPN connection to my NT box over NAT.. Well that sucks.
Thanks for the info!
Greg
----- Original Message -----
From: "Ric Messier" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, May 30, 2000 2:01 PM
Subject: Re: VPN through NAT
VPNs don't typically work through NAT. The reason is that the packet is
altered by the router on the way through the network. As a result, the
signature is altered and the packet is discarded as being corrupt. The
originating IP is used as part of the authentication mechanism for the
packets coming through. It's a security feature.
Ric
----- Original Message -----
From: "Balharek, Peter" <[EMAIL PROTECTED]>
To: "Greg Smythe" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Tuesday, May 30, 2000 4:31 PM
Subject: RE: VPN through NAT
> Try a crazy search on CCO.
>
> Type in "nat vpn".
> Select to search in support.
>
> Ohhh.
>
> Rtfm
>
>
>
> -----Original Message-----
> From: Greg Smythe [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, May 30, 2000 12:55 PM
> To: [EMAIL PROTECTED]
> Subject: VPN through NAT
>
> Hello --
>
> Has anyone done this before? I'm trying to get a VPN
> connection to work over
> NAT. I see the translation happening, but my PC gets as far
> as "verifying
> username/pass" and then it errors out saying the server
> didn't respond
> (timeout).
> show ip nat tra:
>
> tcp 3.3.3.3:1056 102.153.102.251:1056 1.1.1.1:1723
> 1.1.1.1:1723
>
> 3.3.3.3 is the IP of my router's internet interface.
> 102.153.102.251 is my
> inside IP of my pc. 1.1.1.1 is my VPN server on the
> internet.
>
> If I give my PC an internet IP then it works, so it has
> something to do with
> the NAT. No filters are in effect on the interfaces on my
> router.
>
> Thanks!
>
>
> Greg
>
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