UDP port 1985 is HSRP and the destination address of HSRP hello packets is the all routers multicast address (18.104.22.168). The source address is the router's primary IP address assigned to the interface.
Fast-switched packets do not generate messages.
I will try and find out why this is getting logged.
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...