The UpwardPro.com network uses an IP proxy that provides Network Address Translation. Ted implements IPSec for all the internet bound traffic, but observes that he is still not able to access the Internet. What has led to this issue?

Question

Quizplus · Accepted Answer

NAT does not work with IPSec since the packet gets discarded by the receiving end of the VPN connection.
Key Takeaway: A conventional NAT does not work on IPSec packets because when the packet goes through a NAT device, the source address in the packet changes, thereby invalidating the packet. When this happens, the receiving end of the VPN connection discards the packet and the VPN connection negotiations fail.