It's not an option to keep the ISA inline unless there's no other choice. Regarding point# 2; will the PIX be able to do time-based ACL based on username (authenticated through LDAP) or it will just apply the rules to all the users?
Normally time based ACL is for all users, but perhaps you could do something with downloadable ACLs from an Cisco ACS server. The ACS would check AD and map users into groups, the groups could have downloadable time-based ACLs.
PIX alone wil not do what you want, but I think perhaps adding an ACS would do.
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...