Domain Name System (DNS) Parameters 2022-05-26 2026-04-01 0-65279 Expert Review 65280-65534 Private Use Benjamin Schwartz, David Lawrence 0 mandatory Mandatory keys in this RR IETF RFC9460, Section 8 1 alpn Additional supported protocols IETF RFC9460, Section 7.1 2 no-default-alpn No support for default protocol IETF RFC9460, Section 7.1 3 port Port for alternative endpoint IETF RFC9460, Section 7.2 4 ipv4hint IPv4 address hints IETF RFC9460, Section 7.3 5 ech TLS Encrypted ClientHello Config IETF 6 ipv6hint IPv6 address hints IETF RFC9460, Section 7.3 7 dohpath DNS over HTTPS path template IETF 8 ohttp Denotes that a service operates an Oblivious HTTP target IETF RFC9540, Section 4 9 tls-supported-groups Supported groups in TLS IETF draft-ietf-tls-key-share-prediction-01, Section 3.1 10 docpath DNS over CoAP resource path IETF RFC9953, Section 3 11-65279 Unassigned 65280-65534 N/A Reserved for Private Use IETF 65535 N/A Reserved ("Invalid key") IETF