Security review of draft-shore-icmp-aup-06 An Acceptable Use Policy for New ICMP Types and Codes Do not be alarmed. I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. The document discusses the current uses of ICMP and how it may or may not fit into management or control planes, depending on your view of what those are. The recommendation is to limit uses to reporting downstream forwarding anomalies, discovering on-link routers and hosts and network parameters. "ICMP should not be used as a routing or network management protocol." While there are ostensibly no new security considerations, it is worthwhile noting that ICMP plays a part in the Photuris protocol and was also used in SKIP (though that usage is deprecated). In general, I have some concern about using ICMP to discover network security parameters or to report on network security anomalies in the forwarding plane. I would recommend adding something to the security considerations about avoiding such usage or using special caution if defining new protocols. Hilarie