Domain Name System Media Types
simon@josefsson.orgThis document register the media types application/dns and
text/dns, in accordance with RFC 2048 . The application/dns media type is used to identify data on
the detached Domain Name System (DNS) format described in RFC
2540 . The text/dns media type is
used to identify master files as described in RFC 1035 .Domain Name System (DNS) information is traditionally
stored in text files, so called master files or zone files.
The format is described in section 5 of RFC 1035 .DNS data can also be stored in a "detached" format,
intended for archiving purposes, described in RFC 2540 .This document register MIME media types for the two data
formats, following the registration procedures described in
RFC 2048 .MIME media type name: applicationMIME subtype name: dnsRequired parameters: None.Optional parameters: None.Encoding considerations: The data format is binary, and
data must be transfered unmodified. Using encodings intended
for textual parts is not recommended.Security considerations: This media type identify content
as being detached DNS information, as documented in RFC 2540
. This data may be security relevant
according to RFC 2538 , or secured
information according to RFC 2535 .
Securing the content further may be done by standard
techniques, such as OpenPGP or CMS
, but this is outside of the scope
here. Further security assessments are not available at this
point.Interoperability considerations: The encoding of detached
DNS information is, unlike textual master files, well defined.
No further interoperability considerations are known.Published specification: The format of data that could be
tagged with this media type is documented in RFC 2540 .Applications which use this media type: DNS related
software, including software storing and using certificates
stored in DNS.Person & email address to contact for further information:Simon Josefsson simon@josefsson.orgIntended usage: LIMITED USEAuthor/Change controller: simon@josefsson.orgMIME media type name: textMIME subtype name: dnsRequired parameters: None.Optional parameters: None.Encoding considerations: The data is textual, and should be
transferred in a line oriented mode. Text literals may contain
CRLF within the text. Binary transports is possible between
systems that use the same end-of-line conventions. Master
files are in general ASCII, but non-ASCII octet values may
occur and are treated as opaque values by DNS software
(compare RFC 1035 section 5). The master file format permits
encoding arbitrary octet values using the "\DDD" encoding.
The use of "\DDD" encoding can be more reliable than
transporting non-ASCII through MIME transports, if data passes
through a gateway that re-encode the character data.Security considerations: This media type identify content
as being DNS information in "master file" format, as
documented in RFC 1035 . The DNS data
may be security relevant according to RFC 2538 , or secured information according to RFC
2535 . Securing the content further
may be done by standard techniques, such as OpenPGP or CMS , but this
is outside of the scope here. Further security assessments are
not available at this point.Interoperability considerations: There are interoperability
concerns with master files, due to the wide spread use of
vendor specific extensions. Non-ASCII comments within master
files may have been encoded in a locally chosen character
sets, that can be difficult to transport interoperable.
Non-ASCII data in general can become corrupted by re-encoding
gateways. To achieve interoperability, you can use the master
file format described in the specification and the "\DDD"
encoding for non-ASCII octets.Published specification: The format of data that could be
tagged with this MIME type is documented in RFC 1035 .Applications which use this media type: DNS related
software, including software storing and using certificates
stored in DNS.Person & email address to contact for further information:Simon Josefsson simon@josefsson.orgIntended usage: LIMITED USEAuthor/Change controller: simon@josefsson.orgSecurity considerations are discussed in the security
considerations clause of the MIME registrations in section 2 and
3.The IANA is asked to register the MIME media types
application/dns and text/dns using the registration templates in
section 2 and 3, according to the procedure described in RFC 2048
.Thanks to D. Eastlake for suggesting text/dns. Thanks to Keith
Moore for reviewing earlier versions of this document. The author
acknowledges the RSA Laboratories for supporting the work that led
to this document.