NLnet Labs has a long history of supporting an Open Internet and Open Standards. Unbound strives to be a reference implementation for emerging standards in the Internet Engineering Task Force (IETF).

The aim is to implement well-established Internet Drafts as a compile option and drafts in the final stage of open community review as an optional feature, that is disabled by default. Accepted RFCs are implemented in Unbound according to the described standard.

The following table provides an extensive overview of all the RFC standards and Internet drafts that have been implemented in Unbound.

RFC 1034 Domain Names – Concepts and Facilities
RFC 1035 Domain Names – Implementation and Specifciation
RFC 1101 DNS Encoding of Network Names and Other Types
RFC 1123 Requirements for Internet Hosts -- Application and Support
RFC 1183 New DNS RR Definitions
RFC 1337 TIME-WAIT Assassination Hazards in TCP
RFC 1521 MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies
RFC 1706 DNS NSAP Resource Records
RFC 1712 DNS Encoding of Geographical Location
RFC 1876 A Means for Expressing Location Information in the Domain Name System
RFC 1982 Serial Number Arithmetic
RFC 1995 Incremental Zone Transfer in DNS
RFC 1996 A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)
RFC 2163 Using the Internet DNS to Distribute MIXER Conformant Global Address Mapping (MCGAM)
RFC 2181 Clarifications to the DNS Specification
RFC 2182 Selection and Operation of Secondary DNS Servers
RFC 2230 Key Exchange Delegation Record for the DNS
RFC 2253 Lightweight Directory Access Protocol (v3): UTF-8 String Representation of Distinguished Names
RFC 2308 Negative Caching of DNS Queries (DNS NCACHE)
RFC 2535 Domain Name System Security Extensions
RFC 2536 DSA KEYs and SIGs in the Domain Name System (DNS)
RFC 2537 RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)
RFC 2538 Storing Certificates in the Domain Name System (DNS)
RFC 2539 Storage of Diffie-Hellman Keys in the Domain Name System (DNS)
RFC 2606 Reserved Top Level DNS Names
RFC 2671 Extension Mechanisms for DNS (EDNS0)
RFC 2672 Non-Terminal DNS Name Redirection
RFC 2673 Binary Labels in the Domain Name System
RFC 2782 A DNS RR for specifying the location of services (DNS SRV)
RFC 2874 DNS Extensions to Support IPv6 Address Aggregation and Renumbering
RFC 2915 The Naming Authority Pointer (NAPTR) DNS Resource Record
RFC 2930 Secret Key Establishment for DNS (TKEY RR)
RFC 3110 RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)
RFC 3123 A DNS RR Type for Lists of Address Prefixes (APL RR)
RFC 3225 Indicating Resolver Support of DNSSEC
RFC 3526 More Modular Exponential (MODP) Diffie-Hellman groups for Internet Key Exchange (IKE)
RFC 3597 Handling of Unknown DNS Resource Record (RR) Types
RFC 3779 X.509 Extensions for IP Addresses and AS Identifiers
RFC 4007 IPv6 Scoped Address Architecture
RFC 4025 A Method for Storing IPsec Keying Material in DNS
RFC 4033 DNS Security Introduction and Requirements
RFC 4034 Resource Records for the DNS Security Extensions
RFC 4035 Protocol Modifications for the DNS Security Extensions
RFC 4255 Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints
RFC 4343 Domain Name System (DNS) Case Insensitivity Clarification
RFC 4398 Storing Certificates in the Domain Name System (DNS)
RFC 4431 The DNSSEC Lookaside Validation (DLV) DNS Resource Record
RFC 4509 Use of SHA-256 in DNSSEC Delegation Signer (DS) Resource Records (RRs)
RFC 4592 The Role of Wildcards in the Domain Name System
RFC 4597 Conferencing Scenarios
RFC 4697 Observed DNS Resolution Misbehavior
RFC 4701 A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR)
RFC 5001 DNS Name Server Identifier (NSID) Option
RFC 5011 Automated Updates of DNS Security (DNSSEC) Trust Anchors
RFC 5114 Additional Diffie-Hellman Groups for Use with IETF Standards
RFC 5155 DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
RFC 5205 Host Identity Protocol (HIP) Domain Name System (DNS) Extension
RFC 5358 Preventing Use of Recursive Nameservers in Reflector Attacks
RFC 5452 Measures for Making DNS More Resilient against Forged Answers
RFC 5702 Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC
RFC 5933 Use of GOST Signature Algorithms in DNSKEY and RRSIG Resource Records for DNSSEC
RFC 6146 Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers
RFC 6147 DNS64: DNS Extensions for Network Address Translation from IPv6 Clients to IPv4 Servers
RFC 6234 US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)
RFC 6303 Locally Served DNS Zones
RFC 6598 IANA-Reserved IPv4 Prefix for Shared Address Space
RFC 6604 xNAME RCODE and Status Bits Clarification
RFC 6605 Elliptic Curve Digital Signature Algorithm (DSA) for DNSSEC
RFC 6672 DNAME Redirection in the DNS
RFC 6698 The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA
RFC 6725 DNS Security (DNSSEC) DNSKEY Algorithm IANA Registry Updates
RFC 6742 DNS Resource Records for the Identifier-Locator Network Protocol (ILNP)
RFC 6761 Special-Use Domain Names
RFC 6840 Clarifications and Implementation Notes for DNS Security (DNSSEC)
RFC 6844 DNS Certification Authority Authorization (CAA) Resource Record
RFC 6891 Extension Mechanisms for DNS (EDNS(0))
RFC 6975 Signaling Cryptographic Algorithm Understanding in DNS Security Extensions (DNSSEC)
RFC 7043 Resource Records for EUI-48 and EUI-64 Addresses in the DNS
RFC 7344 Automating DNSSEC Delegation Trust Maintenance
RFC 7413 TCP Fast Open
RFC 7477 Child-to-Parent Synchronization in DNS
RFC 7553 The Uniform Resource Identifier (URI) DNS Resource Record
RFC 7646 Definition and Use of DNSSEC Negative Trust Anchors
RFC 7686 The ".onion" Special-Use Domain Name
RFC 7706 Decreasing Access Time to Root Servers by Running One on Loopback
RFC 7766 DNS Transport over TCP - Implementation Requirements
RFC 7830 The EDNS(0) Padding Option
RFC 7858 Specification for DNS over Transport Layer Security (TLS)
RFC 7871 Client Subnet in DNS Queries
RFC 7873 Domain Name System (DNS) Cookies
RFC 7929 DNS-Based Authentication of Named Entities (DANE) Bindings for OpenPGP
RFC 7958 DNSSEC Trust Anchor Publication for the Root Zone
RFC 8020 NXDOMAIN: There Really Is Nothing Underneath
RFC 8080 Edwards-Curve Digital Security Algorithm (EdDSA) for DNSSEC
RFC 8145 Signaling Trust Anchor Knowledge in DNS Security Extensions (DNSSEC)
RFC 8162 Using Secure DNS to Associate Certificates with Domain Names for S/MIME
RFC 8198 Aggressive Use of DNSSEC-Validated Cache
RFC 8310 Usage Profiles for DNS over TLS and DNS over DTLS
RFC 8375 Special-Use Domain 'home.arpa.'
RFC 8467 Padding Policies for Extension Mechanisms for DNS (EDNS(0))
RFC 8482 Providing Minimal-Sized Responses to DNS Queries That Have QTYPE=ANY
RFC 8484 DNS Queries over HTTPS (DoH)
RFC 8509 A Root Key Trust Anchor Sentinel for DNSSEC
RFC 8624 Algorithm Implementation Requirements and Usage Guidance for DNSSEC
RFC 8767 Serving Stale Data to Improve DNS Resiliency
RFC 8806 Running a Root Server Local to a Resolver
RFC 8914 Extended DNS Errors
RFC 8976 Message Digest for DNS Zones
RFC 9018 Interoperable Domain Name System (DNS) Server Cookies
RFC 9156 DNS Query Name Minimisation to Improve Privacy
RFC 9210 DNS Transport over TCP - Operational Requirements