By default on Cisco ASA, IKE runs in aggressive mode for only remote-access VPNs using preshared-key authentication, and this is a requirement for the connection to be successful due to the identity-matching mechanism.
If no changes has been done on your client side then default selection for IKE negotiation will be Main mode.
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...