Ericsson Symantec Additional security concerns with Teredo are documented, beyond what is in RFC 4380. This is based on an independent analysis of Teredo's security implications. The primary intent of this document is to provide information and recommendations to the IETF that can be used in any updated Teredo specification. The second intended audience is anyone that can help improve security in Teredo as deployed, so they will be aware of these concerns.