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Iana Registries MCP Server

io.github.cyanheads/iana-registries-mcp-server

Find IANA ports, MIME types, HTTP codes/fields, URI schemes, PENs, BCP 47 tags, RFCs, any registry.

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URL: https://iana-registries.caseyjhand.com/mcp

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Pulled straight from the server with tools/list on 2026-10-17.
iana_lookup_portread-only

Look up IANA service name and transport protocol port assignments. Pass exactly one of `port` (a number, 0–65535), `service` (an exact service name such as "postgresql"), or `keyword` (words matched against service names and descriptions). Results list every transport (tcp, udp, sctp, dccp) separately, report the registry range row containing an unassigned port, and classify the port as System (

iana_lookup_media_typeread-only

Look up registered media (MIME) types. Pass exactly one of `type` (a full name such as "application/json"; parameters after ";" are ignored) or `keyword` (words matched against registered type names and status annotations, e.g. "geo json"; never against file extensions). An exact `type` lookup also reads the registration template and returns its file-extension, intended-usage, and deprecated-alias

iana_lookup_http_statusread-only

Look up an HTTP status code in the IANA registry, or search reason phrases. Pass exactly one of `code` (100–599) or `keyword` (e.g. "too many"). Returns the registered phrase, its class, defining reference with section, and whether it is temporary, obsoleted, or unused; an unassigned code returns found: false with the unassigned range it falls in.

iana_lookup_http_fieldread-only

Look up a registered HTTP field (header or trailer) name. Pass exactly one of `name` (case-insensitive, e.g. "Cache-Status") or `keyword` (words matched against field names and comments). Returns the registration status — permanent, provisional, deprecated, or obsoleted — the Structured Field type when registered, and the defining reference. Many widely used headers are unregistered; a miss me

iana_lookup_uri_schemeread-only

Look up a registered URI scheme. Pass exactly one of `scheme` (e.g. "mailto"; a trailing ":" or "://" is ignored) or `keyword` (words matched against scheme names and descriptions). Returns the status — permanent, provisional, or historical — description, references, and well-known URI support.

iana_lookup_penread-only

Look up a Private Enterprise Number (PEN). Pass exactly one of `pen` (a number such as 32473, or an OID under 1.3.6.1.4.1 such as 1.3.6.1.4.1.32473.1.2) or `organization` (words matched against organization names). Returns the organization and its OID prefix. Arcs below the enterprise number are assigned by the enterprise, not IANA. Contact details are not returned.

iana_lookup_language_tagread-only

Parse and validate a BCP 47 language tag against the IANA Language Subtag Registry, or search subtags by description. Pass exactly one of `tag` (e.g. "zh-Hant-TW", "sr-Latn", "en_US") or `description` (e.g. "Swiss German"). A tag is split into language, extlang, script, region, variant, extension, and private-use parts; each part is checked, deprecated subtags report their preferred value, and a c

iana_get_rfc_statusread-only

Get the current status of up to 10 RFCs, Internet-Drafts, or BCP/STD/FYI series in one call. Accepts "RFC 9110", "rfc9110", "9110", draft names with or without a revision suffix ("draft-ietf-httpbis-semantics-19"), series numbers ("BCP 14"), RFC and draft file names ("rfc9110.txt"), the URL of an RFC or draft on datatracker.ietf.org, tools.ietf.org, or ietf.org or of an RFC on rfc-editor.org, and

iana_search_registriesread-only

Find IANA protocol registries and sub-registries by keyword over their titles and protocol categories, e.g. "tls cipher", "dns resource record", "protocol numbers". Returns the registry and sub-registry ids that iana_get_registry_records reads, with registration procedure and defining documents. Covers every registry linked from the IANA protocol registries index.

iana_get_registry_recordsread-only

Read records from any IANA XML registry by id, e.g. registry "tls-parameters" with subregistry "tls-parameters-4" (TLS Cipher Suites), "protocol-numbers", "http-methods", or "cbor-tags"; an iana.org/assignments URL also works. Filter with `value` (exact match on the key column, or on the column `field` names; digits compare by number with a cell of digits ("0443" finds "443") and one 0x token with

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