rfc-4143

Facsimile Using Internet Mail (IFAX) Service of ENUM

K. Toyoda, D. Crocker

date2005-11 streamIETF areaapp wgfax statusPROPOSED STANDARD pages5 canonicalhttps://www.rfc-editor.org/rfc/rfc4143 doi10.17487/RFC4143 errataview

This document describes the functional specification and definition of the ENUM Naming Authority Pointer (NAPTR) record for IFax service. IFax is "facsimile using Internet mail". For this use, the Domain Name System (DNS) returns the email address of the referenced IFax system. This mechanism allows email-based fax communication to use telephone numbers instead of requiring the sender to already know the recipient email address. [STANDARDS-TRACK]

updated by

rfc-6118 — Update of Legacy IANA Registrations of Enumservices

Extracted elements (10)

design-rationale §2

The 'mailto' URI scheme was chosen for IFax ENUM because facsimile using Internet mail is a profile of standard Internet mail and uses standard Internet mail addressing, keeping the mechanism consistent with email infrastructure.

email, dns

interoperability-note §1

The email address returned by the ENUM NAPTR query is used in accordance with Simple Mode of Facsimile using Internet Mail (RFC 3965), Extended Facsimile using Internet Mail (RFC 2532), or Full Mode Fax Profile for Internet Mail (RFC 4142).

normative-requirement §3 MUST

The data subject MUST give explicit informed consent before their data is published in ENUM, due to the implications of storing information in a globally accessible database.

dns, privacy, security

protocol-element §2

The IFax ENUM service is identified by the service name 'E2U+ifax', with type 'ifax' and subtype 'mailto'. An IFax client queries ENUM using the target telephone number and receives a NAPTR record specifying a mailto URI for the target system.

dns, email

protocol-element §2

The URI scheme for IFax ENUM NAPTR records is 'mailto', because facsimile using Internet mail is a profile of standard Internet mail and uses standard Internet mail addressing.

dns, email

registry §5

This document creates a DNS NAPTR service registration for 'E2U+ifax' (type 'ifax', subtype 'mailto', URI scheme 'mailto') in the ENUM service registry per RFC 3761.

dns, registry, email

security-consideration §3

ENUM stores data in a globally distributed DNS database visible to anyone anonymously, exposing data subjects to automatic harvesting without notification. Publication of a telephone number linked to an IFax service can enable 'junk fax' spam.

dns, security, privacy

security-consideration §3

Implementers and users of IFax ENUM must also consider the security considerations in RFC 3965 (Simple Mode Fax), RFC 2532 (Extended Fax), and the ENUMbis specification (RFC 3761), all of which apply to this document.

security, email, dns

security-consideration §3

Unlike email where users can use sacrificial accounts to filter spam, PSTN E.164 numbers are inflexible and cannot be substituted with a throwaway number, making spam mitigation harder for IFax users.

security, email

wire-format §4

An IFax NAPTR record uses the 'u' flag, service field 'E2U+ifax:mailto', and a regex that maps any input to a mailto URI, as shown: IN NAPTR 10 10 "u" "E2U+ifax:mailto" "!^.*$!mailto:[email protected]!".

dns, email