To drop the packets, you would do something like the following (assuming e0 is your inside interface and s0 is your outside):
set ip dscp 1
service-policy input block-p2p
ip access-group 100 out
access-list 100 deny ip any any dscp 1
access-list 100 permit ip any any
Basically you set the DSCP bit in the IP header on all packets that match the policy-map as they come in on e0, then use an outbound access-list on s0 to drop all packets with the DSCP bit set. Nothing uses the DSCP bit in normal circumstances.
You can check Method B and C on the above URL as these might suit you better. Method C actually allows the traffic through but applies rate-limiting to it.
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...