diff --git a/draft-ietf-core-dns-over-coap.md b/draft-ietf-core-dns-over-coap.md index 427e982..197887c 100644 --- a/draft-ietf-core-dns-over-coap.md +++ b/draft-ietf-core-dns-over-coap.md @@ -351,18 +351,12 @@ mapping between any other DNS transport. Considerations for Unencrypted Use {#sec:unencrypted-coap} ================================== -While not recommended, -DoC can be used without any encryption -e.g., in very constrained environments where encryption is not possible or necessary. -It can also be used when lower layers provide secure communication between client and server. -In both cases, -potential benefits of -unencrypted DoC usage over classic DNS are e.g. block-wise transfer or alternative CoAP -Content-Formats to overcome link-layer constraints. -For unencrypted DoC usage the ID of the DNS message MAY still be set to 0 to leverage the cache -benefits described in {{sec:req-caching}}. -In this case an unpredictable token MUST be picked for each CoAP request that carries such a DNS -message. +The use of DoC without a security mode of CoAP is NOT RECOMMENDED. +Without a security mode, a large number of possible attacks need to be evaluate in the context of +the application's threat model. +This includes threats that are mitigated even by DNS over UDP: +For example, the random ID of the DNS header afford some protection against off-path cache poisoning +attacks---a threat that might be mitigated by using random large token values in the CoAP request. Implementation Status