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. I apologize for the delay in getting this review out. Hopefully it is still useful. This first set of comments is primarily for the authors. 1. In section 4.4.4 on Data origin authentication the last paragraph states that only the 3rd of the above conditions is acceptable, do you really mean the 4th? 2. In section 4.4.4 there is reference to the packet including a digital signature to authenticate the origin. What is the signature mechanism? Is this SEND or something different? I did not see a reference to it. 3. The security considerations do not say much about the consequences of trusting an inappropriate intermediate router, ingress node or egress node. Clearly DOS to the ingress node is a possibility. Data modification and disclosure can be a goal of an attacker who tries to control the routing. Are there other issues the reader should be aware of (perhaps other DOS attacks such as amplification attacks). Anything outside the considerations of RFC4861)? 4. The security consideration section indicates that spoofing protection can be provided by links that provide link layer security mechanisms. Link Layer security mechanisms may or may not help. I believe more information is needed here. L2 mechanisms may not provide adequate protection of upper layer address bindings. In some cases L2 mechanisms do not provide source origin authentication such as multicast traffic protected with the group key in WiFi and group security associations in 802.1AE (MACSEC). This set of comments is mostly for the area directors: 1. I am mostly concerned about the lack of definition for the digital signature mechanism. Perhaps this is easily rectified by a reference to an existing specification. Its not clear to me what the specification would be (perhaps SEND??)? Is something needed in addition? 2. The risks of not securing the proposal are not defined in the security considerations section. I think this would be helpful, but may not be strictly necessary. There is some mention of Link-Layer security helping in some aspects of this, but its not clear on what characteristics the lower layer security needs to provide. Cheers, Joe