NAPTR Records

NAPTR (Naming Authority Pointer) RECORD INFORMATION

A newer type of DNS record that support regular expression based rewriting.

NAPTR Records info

This record set maps the phone number +441632960083 onto three possible identically ordered URIs, with a preference for SIP, then H323, and finally email. In each case, the regular expression matches the full AUS (^.$), and replaces it with a URI (e.g., As this is a terminal record, this URI is returned to the client.Though most NAPTR records replace the full AUS, it is possible for the regular expression to back-reference part of the AUS, to grab an extension number, say:

Once the client has the URI it must be resolved using DNS, but this is no longer part of the DDDS algorithm..


Host can be an @ character (most common) or an alpha-numeric string with periods, hyphens and underscores. Doesn't have to be a Fully Qualified Domain Name (FQDN)

Data (Example)

$ORIGIN NAPTR 10 100 "u" "E2U+sip" "!^.*$!!" . NAPTR 10 101 "u" "E2U+h323" "!^.*$!!" . NAPTR 10 102 "u" "E2U+msg" "!^.*$!!" .

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