Perfect Forward Secrecy (PFS)-PFS ensures that a given IPsec SA key was not derived from any other secret, like some other keys. In other words, if someone breaks a key, PFS ensures that the attacker is not able to derive any other key. If PFS is not enabled, someone can potentially break the IKE SA secret key, copy all the IPsec protected data, and then use knowledge of the IKE SA secret in order to compromise the IPsec SAs setup by this IKE SA. With PFS, breaking IKE does not give an attacker immediate access to IPsec. The attacker needs to break each IPsec SA individually. The Cisco IOS IPsec implementation uses PFS group 1 (D-H 768 bit) by default.
Also reference this thread's answer well put together.
Will that mean that in case of PFS IPSec SA will use its own keys(not derived from IKE SA Keys) OR PFS will just protect the IPSec keys from getting broken though the IPSec keys are derived from IKE SA keys
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...