Discussion of Requirements for ADD

Several DNS encryption technologies have been introduced, including DNS-over-TLS and DNS-over-HTTPS and so on. The work of the Adaptive DNS Discovery working group includes supporting client discovery of encrypted DNS resolution services and communication mechanisms for selection decisions. Since the proposal of the draft plan should be guided by the existing problems, the working group should first reach a consensus on the problems to be solved and the principles applicable to each problem, and then promote follow-up work on this basis. This document discusses various usage scenarios and corresponding requirements for discovering and using encrypted DNS technology.

Encrypted DNS: DNS-over-HTTPS, DNS-over-TLS or any other encrypted DNS technology that the IETF may publish, for example, DNS-over-QUIC .

The DNS client accesses the recursive server with discovery function, and the discussion is divided into the following situations:

1) Ordinary DNS resolution service The client can automatically obtain the common DNS recursive resolution server address through DHCP. 2) Encrypted DNS resolution service The client can choose several types of encryption resolution services currently provided (such as DOH/DOT, etc.), and accept the default configuration of the recursive server. The encrypted DNS recursive resolution server address can be automatically set through DHCP/RA/PPP and other protocols.

If the client has been configured with parameters, the following two aspects are initially considered for configuration parameters: 1) For general DNS resolution services, the client can update and configure the encrypted DNS recursive resolution server type and address. This method is suitable for common networks and specific networks. 2) Users can set to use the specified encrypted DNS resolution service when accessing certain specific domain names. Set up a list of mapping relationships between domain names and DNS resolution service addresses.

We can provide an encrypted DNS recursive resolution server address list, which can be publicly maintained and updated regularly. The priority of selecting an encrypted DNS resolver is determined by the server's own design. Currently Mozilla maintains a similar list relationship.

If some companies or institutions want to use their own encrypted DNS resolution service when accessing their own domain names, they will provide the resolution server through the mapping relationship.

To be added.

The authors would like to thank Jiankang Yao, and Linlin Zhou for their careful review and valuable comments.