rfc1035.txt

bind 9.3结合mysql数据库

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    /                   NSDNAME                     /
    /                                               /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

NSDNAME         A <domain-name> which specifies a host which should be
                authoritative for the specified class and domain.

NS records cause both the usual additional section processing to locate
a type A record, and, when used in a referral, a special search of the
zone in which they reside for glue information.

The NS RR states that the named host should be expected to have a zone
starting at owner name of the specified class.  Note that the class may
not indicate the protocol family which should be used to communicate
with the host, although it is typically a strong hint.  For example,
hosts which are name servers for either Internet (IN) or Hesiod (HS)
class information are normally queried using IN class protocols.

3.3.12. PTR RDATA format

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    /                   PTRDNAME                    /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

PTRDNAME        A <domain-name> which points to some location in the
                domain name space.

PTR records cause no additional section processing.  These RRs are used
in special domains to point to some other location in the domain space.
These records are simple data, and don't imply any special processing
similar to that performed by CNAME, which identifies aliases.  See the
description of the IN-ADDR.ARPA domain for an example.








Mockapetris                                                    [Page 18]

RFC 1035        Domain Implementation and Specification    November 1987


3.3.13. SOA RDATA format

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    /                     MNAME                     /
    /                                               /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    /                     RNAME                     /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    SERIAL                     |
    |                                               |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    REFRESH                    |
    |                                               |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                     RETRY                     |
    |                                               |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    EXPIRE                     |
    |                                               |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    MINIMUM                    |
    |                                               |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

MNAME           The <domain-name> of the name server that was the
                original or primary source of data for this zone.

RNAME           A <domain-name> which specifies the mailbox of the
                person responsible for this zone.

SERIAL          The unsigned 32 bit version number of the original copy
                of the zone.  Zone transfers preserve this value.  This
                value wraps and should be compared using sequence space
                arithmetic.

REFRESH         A 32 bit time interval before the zone should be
                refreshed.

RETRY           A 32 bit time interval that should elapse before a
                failed refresh should be retried.

EXPIRE          A 32 bit time value that specifies the upper limit on
                the time interval that can elapse before the zone is no
                longer authoritative.





Mockapetris                                                    [Page 19]

RFC 1035        Domain Implementation and Specification    November 1987


MINIMUM         The unsigned 32 bit minimum TTL field that should be
                exported with any RR from this zone.

SOA records cause no additional section processing.

All times are in units of seconds.

Most of these fields are pertinent only for name server maintenance
operations.  However, MINIMUM is used in all query operations that
retrieve RRs from a zone.  Whenever a RR is sent in a response to a
query, the TTL field is set to the maximum of the TTL field from the RR
and the MINIMUM field in the appropriate SOA.  Thus MINIMUM is a lower
bound on the TTL field for all RRs in a zone.  Note that this use of
MINIMUM should occur when the RRs are copied into the response and not
when the zone is loaded from a master file or via a zone transfer.  The
reason for this provison is to allow future dynamic update facilities to
change the SOA RR with known semantics.


3.3.14. TXT RDATA format

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    /                   TXT-DATA                    /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

TXT-DATA        One or more <character-string>s.

TXT RRs are used to hold descriptive text.  The semantics of the text
depends on the domain where it is found.

3.4. Internet specific RRs

3.4.1. A RDATA format

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    ADDRESS                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

ADDRESS         A 32 bit Internet address.

Hosts that have multiple Internet addresses will have multiple A
records.





Mockapetris                                                    [Page 20]

RFC 1035        Domain Implementation and Specification    November 1987


A records cause no additional section processing.  The RDATA section of
an A line in a master file is an Internet address expressed as four
decimal numbers separated by dots without any imbedded spaces (e.g.,
"10.2.0.52" or "192.0.5.6").

3.4.2. WKS RDATA format

    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |                    ADDRESS                    |
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    |       PROTOCOL        |                       |
    +--+--+--+--+--+--+--+--+                       |
    |                                               |
    /                   <BIT MAP>                   /
    /                                               /
    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

where:

ADDRESS         An 32 bit Internet address

PROTOCOL        An 8 bit IP protocol number

<BIT MAP>       A variable length bit map.  The bit map must be a
                multiple of 8 bits long.

The WKS record is used to describe the well known services supported by
a particular protocol on a particular internet address.  The PROTOCOL
field specifies an IP protocol number, and the bit map has one bit per
port of the specified protocol.  The first bit corresponds to port 0,
the second to port 1, etc.  If the bit map does not include a bit for a
protocol of interest, that bit is assumed zero.  The appropriate values
and mnemonics for ports and protocols are specified in [RFC-1010].

For example, if PROTOCOL=TCP (6), the 26th bit corresponds to TCP port
25 (SMTP).  If this bit is set, a SMTP server should be listening on TCP
port 25; if zero, SMTP service is not supported on the specified
address.

The purpose of WKS RRs is to provide availability information for
servers for TCP and UDP.  If a server supports both TCP and UDP, or has
multiple Internet addresses, then multiple WKS RRs are used.

WKS RRs cause no additional section processing.

In master files, both ports and protocols are expressed using mnemonics
or decimal numbers.




Mockapetris                                                    [Page 21]

RFC 1035        Domain Implementation and Specification    November 1987


3.5. IN-ADDR.ARPA domain

The Internet uses a special domain to support gateway location and
Internet address to host mapping.  Other classes may employ a similar
strategy in other domains.  The intent of this domain is to provide a
guaranteed method to perform host address to host name mapping, and to
facilitate queries to locate all gateways on a particular network in the
Internet.

Note that both of these services are similar to functions that could be
performed by inverse queries; the difference is that this part of the
domain name space is structured according to address, and hence can
guarantee that the appropriate data can be located without an exhaustive
search of the domain space.

The domain begins at IN-ADDR.ARPA and has a substructure which follows
the Internet addressing structure.

Domain names in the IN-ADDR.ARPA domain are defined to have up to four
labels in addition to the IN-ADDR.ARPA suffix.  Each label represents
one octet of an Internet address, and is expressed as a character string
for a decimal value in the range 0-255 (with leading zeros omitted
except in the case of a zero octet which is represented by a single
zero).

Host addresses are represented by domain names that have all four labels
specified.  Thus data for Internet address 10.2.0.52 is located at
domain name 52.0.2.10.IN-ADDR.ARPA.  The reversal, though awkward to
read, allows zones to be delegated which are exactly one network of
address space.  For example, 10.IN-ADDR.ARPA can be a zone containing
data for the ARPANET, while 26.IN-ADDR.ARPA can be a separate zone for
MILNET.  Address nodes are used to hold pointers to primary host names
in the normal domain space.

Network numbers correspond to some non-terminal nodes at various depths
in the IN-ADDR.ARPA domain, since Internet network numbers are either 1,
2, or 3 octets.  Network nodes are used to hold pointers to the primary
host names of gateways attached to that network.  Since a gateway is, by
definition, on more than one network, it will typically have two or more
network nodes which point at it.  Gateways will also have host level
pointers at their fully qualified addresses.

Both the gateway pointers at network nodes and the normal host pointers
at full address nodes use the PTR RR to point back to the primary domain
names of the corresponding hosts.

For example, the IN-ADDR.ARPA domain will contain information about the
ISI gateway between net 10 and 26, an MIT gateway from net 10 to MIT's



Mockapetris                                                    [Page 22]

RFC 1035        Domain Implementation and Specification    November 1987


net 18, and hosts A.ISI.EDU and MULTICS.MIT.EDU.  Assuming that ISI
gateway has addresses 10.2.0.22 and 26.0.0.103, and a name MILNET-
GW.ISI.EDU, and the MIT gateway has addresses 10.0.0.77 and 18.10.0.4
and a name GW.LCS.MIT.EDU, the domain database would contain:

    10.IN-ADDR.ARPA.           PTR MILNET-GW.ISI.EDU.
    10.IN-ADDR.ARPA.           PTR GW.LCS.MIT.EDU.
    18.IN-ADDR.ARPA.           PTR GW.LCS.MIT.EDU.
    26.IN-ADDR.ARPA.           PTR MILNET-GW.ISI.EDU.
    22.0.2.10.IN-ADDR.ARPA.    PTR MILNET-GW.ISI.EDU.
    103.0.0.26.IN-ADDR.ARPA.   PTR MILNET-GW.ISI.EDU.
    77.0.0.10.IN-ADDR.ARPA.    PTR GW.LCS.MIT.EDU.
    4.0.10.18.IN-ADDR.ARPA.    PTR GW.LCS.MIT.EDU.
    103.0.3.26.IN-ADDR.ARPA.   PTR A.ISI.EDU.
    6.0.0.10.IN-ADDR.ARPA.     PTR MULTICS.MIT.EDU.

Thus a program which wanted to locate gateways on net 10 would originate
a query of the form QTYPE=PTR, QCLASS=IN, QNAME=10.IN-ADDR.ARPA.  It
would receive two RRs in response:

    10.IN-ADDR.ARPA.           PTR MILNET-GW.ISI.EDU.
    10.IN-ADDR.ARPA.           PTR GW.LCS.MIT.EDU.

The program could then originate QTYPE=A, QCLASS=IN queries for MILNET-
GW.ISI.EDU. and GW.LCS.MIT.EDU. to discover the Internet addresses of
these gateways.

A resolver which wanted to find the host name corresponding to Internet
host address 10.0.0.6 would pursue a query of the form QTYPE=PTR,
QCLASS=IN, QNAME=6.0.0.10.IN-ADDR.ARPA, and would receive:

    6.0.0.10.IN-ADDR.ARPA.     PTR MULTICS.MIT.EDU.

Several cautions apply to the use of these services:
   - Since the IN-ADDR.ARPA special domain and the normal domain
     for a particular host or gateway will be in different zones,
     the possibility exists that that the data may be inconsistent.

   - Gateways will often have two names in separate domains, only
     one of which can be primary.

   - Systems that use the domain database to initialize their
     routing tables must start with enough gateway information to
     guarantee that they can access the appropriate name server.