Internet-Draft Infrastructure .int domains October 2021
Davies & Baber Expires 17 April 2022 [Page]
Network Working Group
1591 (if approved)
Intended Status:
K. Davies
A. Baber

Deprecating infrastructure "int" domains


The document marks as historic any "int" domain names that were designated for infrastructure purposes, and identifies them for removal from the "int" top-level domain. Any implementation that involves these domains should be considered deprecated. This document also updates RFC 1591 by removing the documented use of "int" for international databases.

Status of This Memo

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This Internet-Draft will expire on 17 April 2022.

1. Introduction

The "int" top-level domain [RFC1591] is a specialized domain designated for intergovernmental organizations, which are organizations established by international treaties between or among national governments.

Historically, the "int" domain was also used for Internet infrastructure related purposes. This practice ended in 2001 when the "arpa" domain was declared the appropriate home for infrastructural identifier spaces [RFC3172]. In conjunction with this change, the eligibility for "int" domains was limited to only intergovernmental treaty organizations.

The documented uses of infrastructural identifiers in the "int" domain were largely experimental and in practice obsolete. This document formalizes moving the related specifications to historic status, along with removing any associated delegations from the "int" zone in the domain name system.

2. Historical infrastructural uses

The following domains were used for infrastructural identifier purposes that are now considered historic. Although each of these names was either delegated or documented at one time, the parties administering them have long since stopped using them.


The domain was experimentally defined to implement address lookups for Asynchronous Transfer Mode (ATM), including ATM End System Addresses (AESAs). [ANS]


The domain was described as providing an alternative to domain for mapping host IPv4 addresses to host names. The domain zone continues to be administered for this purpose [RFC1035].


The domain was originally delegated for mapping host IPv6 addresses to host names. It was subsequently removed from the "int" zone, having been replaced by for this purpose [RFC4159].


The domain name was specified to experimentally map Open Systems Interconnection (OSI) Network Service Access Points to domain names [RFC1706].


The domain name experimentally mapped OSI Inter-Domain Routing Protocol's Routing Domain Identifiers [ISO10747] to the domain name system.


The domain name hosted an experimental mechanism for publishing IANA registration values in the domain name system.


The domain name hosted an experimental remote printing service that served as a gateway between Internet mail and facsimile transmission [RFC1528].

3. IANA Considerations

The IANA shall coordinate the removal of any of the historical "int" domains discussed in this document that are still delegated in the "int" zone.

4. Security Considerations

Some old systems might have one or more subdomains of these names hardwired and expect a positive response for at least the second-level domain. This is, of course, true for any name in the DNS and should not be the sole basis to retain obsolete names.

Existing applications should eliminate any reliance upon these zones for their historic purpose. The operator of the "int" domain should be cautious about any potential re-use of these domains for intergovernmental treaty organizations.

5. Additional Information

This document is the result of an comprehensive inventory conducted by the IANA team of .int domains to accurately establish and record their purpose based on historical documentation. Following this review, the remaining domains delegated for infrastructure identifier related purposes were reviewed. As part of this review, query patterns in the DNS were analyzed and judged to be insignificant. The assessment concluded that these domains are highly likely to be obsolete and this document is intended to formalize that assessment.

There are a small number of existing "int" domains nominally for "international databases" that are not defined by any standards documentation, and are assigned to entities rather than for an identifier purpose. While they would not qualify for a "int" domain under current criteria, their disposition is beyond the scope of this memo.

6. Informative References

"ATM Name Service", ATM Forum AF/95-1532R3, n.d..
"Protocol for exchange of inter-domain routeing information among intermediate systems to support forwarding of ISO 8473 PDUs", ISO/IEC 10747:1994, , <>.
Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, , <>.
Malamud, C. and M. Rose, "Principles of Operation for the TPC.INT Subdomain: Remote Printing -- Technical Procedures", RFC 1528, DOI 10.17487/RFC1528, , <>.
Postel, J., "Domain Name System Structure and Delegation", RFC 1591, DOI 10.17487/RFC1591, , <>.
Manning, B. and R. Colella, "DNS NSAP Resource Records", RFC 1706, DOI 10.17487/RFC1706, , <>.
Huston, G., Ed., "Management Guidelines & Operational Requirements for the Address and Routing Parameter Area Domain ("arpa")", BCP 52, RFC 3172, DOI 10.17487/RFC3172, , <>.
Huston, G., "Deprecation of """, BCP 109, RFC 4159, DOI 10.17487/RFC4159, , <>.

Notes (for removal before publication)

I-D source is maintained at:


This document was compiled with help from Ted Hardie and Michelle Cotton, with additional input by Jari Arkko and Warren Kumari.

Authors' Addresses

Kim Davies
Internet Assigned Numbers Authority
12025 Waterfront Drive
Los Angeles, 90094
United States of America
Amanda Baber
Internet Assigned Numbers Authority
12025 Waterfront Drive
Los Angeles, 90094
United States of America