NAT-T can be used between VPN Clients and a concentrator, or between concentrators behind a NAT/PAT device. At this time, this feature is supported only between the Cisco VPN clients (Unity client) and a concentrator, or between concentrators.
Not quite right. NAT-T is supported on routers and PIX's now also.
However, you have the wrong idea of where to configure it. You configure NAT-T on the VPN termination point, in your case the PIX. The intermediate 837 doesn't need to know about anything, as the VPN client and the PIX will encapsulate their IPSec packets into UDP 4500 and the 837 will just NAT them like any other packet.
On the PIX, upgrade it to 6.3 code and use the command:
BenefitsDocumentationPrerequisiteImage Download LinksLimitationsSupported PlatformsLicense RequirementsTopologyStep-By-Step ConfigurationConfigure Virtual ServiceActivate the virtual service and configure guest IPsConfiguring UTD (Service Plane)Configurin...
Login to the FXOS chassis manager.
Direct your browser to https://hostname/, and log-in using the user-name and password.
Go to Help > About and check the current version:
Check the current version availa...
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...