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 dynamic hostname TLV is an optional in-band mechanism to provide human-friendly symbolic names that map to router IDs. The security considerations section 1) encourages the use of OSPF authentication and 2) calls out the grand fun possible if a misconfigured or compromised router sends bad mappings. While that's probably less fun than could be had from just sending bad routing data, it adds an extra level of complexity to the debugging when these new symbolic names, as shown in config and debugging tools, don't match the expected router IDs. But I'm not sure anything more really needs to be said here. Resource exhaustion, as raised by Robert Sparks, looks to be a possibility, but I could go either way on whether it's worth adding words about it specifically -- do we need to call out the potential for resource exhaustion for every field in every protocol? I'd let the doc go as-is. -- Sam