So really I don't think you've solved any problems because... LEO: Well, and the router is doing essentially the same thing as the security gateway.
NIPRNET does have controlled security gateways to the public Internet.
I guess you could extend this to say, what if they're running, say, an Astaro Security Gateway or some sort of security gateway.
IPsec has an end-to-end Transport Mode, but can also operate in a tunneling mode through a trusted security gateway.
They make one of the best security gateways out there, the Astaro Security Gateway.
The device interfaces with software on a corporate server to support company policies and security updates through security gateways.
Fortinet offers security gateways and products that are a blend of ASIC-accelerated performance, integrated multi-threat protection, and constantly-updated, in-depth threat intelligence.
So if you've got an old beige box lying around you want to turn into a security gateway, this is the way to do it.
The device may include a stateful firewall, a VPN concentrator, or be an IPSec security gateway.
A separate product called VPN Power-1 VSX can host multiple virtual security gateways on a single machine.