NAPTR
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... Although this is defining a new and separate DDDS Application, dubbed
U-NAPTR, it is built from the same principles as the Straightforward
NAPTR (S-NAPTR ...
... U-NAPTR, it is built from the same principles as the Straightforward
NAPTR (S-NAPTR) application, specified in [2]. This specification is
...
... U-NAPTR, it is built from the same principles as the Straightforward
NAPTR (S-NAPTR) application, specified in [2]. This specification is
not an update ...
... 2]. This specification is
not an update of S-NAPTR, but the reader is encouraged to review that
document for extensive coverage of motivation and implementation
considerations.
...
... implementation
considerations.
S-NAPTR provides for application service location that does not rely
on rigid domain ...
... domain naming conventions. It is deemed "straightforward"
in part because it rules out the use of regular expressions in NAPTR
records (for the S-NAPTR DDDS Application). However, that also rules
...
... in part because it rules out the use of regular expressions in NAPTR
records (for the S-NAPTR DDDS Application). However, that also rules
out the possibility of providing a URI ...
... resolution. A number of applications, specified (e.g., [9]) and
proposed, find the restriction too limiting, making S-NAPTR a near
miss to suit their needs.
...
... miss to suit their needs.
This U-NAPTR is effectively a modest extension to S-NAPTR, to
accommodate the use of URIs ...
...
This U-NAPTR is effectively a modest extension to S-NAPTR, to
accommodate the use of URIs as targets ...
... Straightforward URI-Enabled NAPTR (U-NAPTR) ...
... Straightforward URI-Enabled NAPTR (U-NAPTR) ...
...
This document assumes the reader is familiar with the S-NAPTR
specification [2]. The intention of U-NAPTR ...
... S-NAPTR
specification [2]. The intention of U-NAPTR is to provide everything
that S-NAPTR does, except that it allows the use of the "U" flag in
...
... 2]. The intention of U-NAPTR is to provide everything
that S-NAPTR does, except that it allows the use of the "U" flag in
the NAPTR record, and a specific form of REGEXP ...
... that S-NAPTR does, except that it allows the use of the "U" flag in
the NAPTR record, and a specific form of REGEXP.
...
...
U-NAPTR permits the same flags as S-NAPTR ("S", "A", or empty), plus
the "U" Flag. For the U-NAPTR ...
...
U-NAPTR permits the same flags as S-NAPTR ("S", "A", or empty), plus
the "U" Flag. For the U-NAPTR DDDS Application ...
... U-NAPTR permits the same flags as S-NAPTR ("S", "A", or empty), plus
the "U" Flag. For the U-NAPTR DDDS Application, the presence of the
"U" Flag in the NAPTR record ...
... U-NAPTR DDDS Application, the presence of the
"U" Flag in the NAPTR record indicates the REGEXP field must be
populated (and, consequently, the REPLACEMENT field is empty). The
...
...
U-NAPTR permits regular expressions of a form that does a complete
replacement of the matched string with a URI ...
... URI, expressed as a constant
string. This is essentially a dodge around the fact that the
REPLACEMENT field in NAPTR is required to produce only a fully
qualified domain name (and, therefore, cannot be used for a URI).
...
... With this limited form of regular expression, applications using
U-NAPTR need not implement full regular expression parsers.
...
... Sample U-NAPTR DNS Records ...
...
In the sample NAPTR RRs for example.com shown below, "WP" is the
imagined application service tag ...
... client obtains a NAPTR RR for a U-NAPTR-using
application that contains any other flag, that NAPTR RR ...
... RR for a U-NAPTR-using
application that contains any other flag, that NAPTR RR should be
ignored and processing continues with the next record (if any).
...
... DDDS algorithm, if the Flag string is empty the
next lookup is for another NAPTR record (for the replacement target).
...
... [4] specifies a DDDS Database that uses the NAPTR DNS resource record
to contain the rewrite rules. The Keys for this database are encoded
...
... domain name, and this is the Key
that is used for the first lookup -- the NAPTR records for that
domain are requested.
...
... DNS servers MAY interpret Flag values and use that information to
include appropriate NAPTR, SRV, or A records in the Additional
...
... the Additional Information Processing section of [4] for more
information on NAPTR records and the Additional Information section
of a DNS response packet.
...
... requirements on IANA, but
provides the basis upon which U-NAPTR-using services can make use of
the existing IANA registries ...
... S-NAPTR; see
Section 8 of [2]. U-NAPTR has the additional consideration that
resolving URIs (from the result of the DDDS ...
... DNSSEC, client
software can be confident that the URI obtained using U-NAPTR is
indeed the one specified by the administrator of the domain ...