This will be a normal signature to see triggered if you are watching outbound traffic from your internal network. As long as the source of the traffic is your internal hosts, and the destination is external hosts, this is likely just normal behavior.
This signature triggers when a single host sends TCP SYN packets to a number of different hosts, perhaps because of multiple web sessions going, or pop-up windows while web surfing.
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...