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RFC 2606 / RESERVED DOMAIN NAMES

Locate the three reserved example domains

03

example.com, example.net and example.org are reserved example names at the second level, below their respective TLDs.

DIAGRAMRead RFC section 3 ↗
RFC 2606 · § 3EXAMPLE
3 / 3
Locate the three reserved example domainsThe root dot branches to com, net and org, which themselves are not RFC2606 example reservations. Exact second-level example.com, example.net and example.org branches appear next. A descendant api.example.org is then selected under example.org; the separate lookalike example.org.other is outside this list. A schematic subset of the DNS tree, not a zone file.Schematic subset of the DNS name tree.comnetorgexampleexampleexampleexample.com · example.net · example.orgapiapi.example.org is a descendantexample.org.other is outside this list
03
Extend a reserved domain by whole labels.

api.example.org is below example.org; example.org.other is not. The latter is a fictional boundary counterexample only, with no assertion about the other TLD’s allocation status.

Source for this drawing: RFC 2606 · Read RFC section 3 ↗

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RFC 1034 DNS RFC 1918 Private IPv4 addresses

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Related RFCs and changes

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KEY POINT

The reserved second-level list in RFC 2606 is exactly example.com, example.net and example.org. It is distinct from the top-level .example reservation.

  • The reserved second-level list in RFC 2606 is exactly example.com, example.net and example.org. It is distinct from the top-level .example reservation.
  • A descendant such as api.example.org falls under example.org. A visually similar name outside a reserved domain does not gain this reservation by resemblance.
  • RFC 6761 §6.5 covers these domains and their descendants, and says caching DNS servers SHOULD resolve example names normally. A reserved example name is not a guarantee of NXDOMAIN or a production service.
DETAILS

Rejected erratum 7304 proposed adding example.edu; it is not adopted here. IANA operation of a domain is not the same as a reservation in these RFCs. Held editorial erratum 7741 is recorded as held, not verified. The original RFC title is retained.

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