Hi, 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. This draft specifies version 2 of mtrace, a multicast traceroute facility. It provides a way to diagnose some issues with multicast like packet loss and isolation of configuration problems. Each router on the reverse path towards a source adds quite a bit of information to a mtrace2 response and the draft discusses how to diagnose problems using this information. mtrace2 seems like a useful tool and can discover quite a bit about a network. The security considerations deal with the fact that some of that information might be restricted and, in that case, recommends not forwarding mtrace2 into the network and replying appropriately-- administratively prohibited. That seems appropriate. I see no issues with this draft. regards, Dan.