Cisco firewall keep the operating system image and firewall configuration (startup-config) in the flash (nonvolatile) memory file system.
When a firewall boots, it uncompresses and copies an executable image from Flash to RAM. The image is actually run from RAM. At this time, the startup configuration commands are copied to the "running" configuration file in RAM (volatile) memory. Any command that is entered or copied into the running configuration is also executed at that time.
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...