Depends what you are trying to do, if it is just device authentication in the group set up set the Default Group to disabled so they are denied access and then create a new group fro device admin, enable it and your users to it either by a group mapping or adding them manually:
User Setup -> Select User -> Group to which the user is assigned:
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...
[toc:faq]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 and UDP are I...