HP-UX Reference (11i v2 03/08) - 1M System Administration Commands N-Z (vol 4)

n
named(1M) named(1M)
opt_domain This field is used to define an origin for the data in an included file. It is equivalent
to placing an $ORIGIN statement before the first line of the included file. The field
is optional. Neither the opt_domain field nor
$ORIGIN statements in the included
file modify the current origin for this file.
opt_ttl An optional integer number for the time-to-live field. It defaults to zero, meaning
the minimum value specified in the SOA record for the zone.
opt_class The object address type; currently only one type is supported, IN, for objects con-
nected to the DARPA Internet.
type This field contains one of the following tokens; the data expected in the
resource_record_data field is in parentheses:
A a host address (dotted-quad IP address)
NS an authoritative name server (domain)
MX a mail exchanger (domain), preceded by a preference value (0..32767), with
lower numeric values representing higher logical preferences.
CNAME the canonical name for an alias (domain)
SOA marks the start of a zone of authority (domain of originating host, domain
address of maintainer, a serial number and the following parameters in
seconds: refresh, retry, expire and minimum TTL (see RFC 883)).
NULL a null resource record (no format or data)
RP a Responsible Person for some domain name (mailbox, TXT-referral)
PTR a domain name pointer (domain)
HINFO host information (cpu_type OS_type)
TXT text data (string)
WKS a well known service description (IP address followed by a list of services)
Resource records normally end at the end of a line, but may be continued across lines between opening
and closing parentheses. Comments are introduced by semicolons and continue to the end of the line.
NOTE: All the db files have to start with a $TTL value. There are other resource record types not
shown here. You should consult the BIND Operations Guide (‘‘BOG’’) for the complete list. Some
resource record types may have been standardized in newer RFCs but not yet implemented in this version
of BIND.
SOA Record Format
Each master zone file should begin with an SOA record for the zone. An example SOA record is as fol-
lows:
@ IN SOA ucbvax.Berkeley.EDU. rwh.ucbvax.Berkeley.EDU. (
1989020501 ; serial
10800 ; refresh
3600 ; retry
3600000 ; expire
86400 ) ; minimum
The SOA specifies a serial number, which should be changed each time the master file is changed. Note
that, it is not advisable to give the serial number as a dotted number, since the translation to normal
integers is via concatenation rather than multiplication and addition. You can spell out the year, month,
day of month, and 0..99 version number and still fit inside the unsigned 32-bit size of this field. (It’s true
that we will have to rethink this strategy in the year 4294.)
Secondary servers check the serial number at intervals specified by the refresh time in seconds; if the
serial number changes, a zone transfer will be done to load the new data. If a master server cannot be
contacted when a refresh is due, the retry time specifies the interval at which refreshes should be
attempted. If a master server cannot be contacted within the interval given by the expire time, all data
from the zone is discarded by secondary servers. The minimum value is the time-to-live (‘‘TTL’’) used by
records in the file with no explicit time-to-live value.
NOTE: The boot file directives domain and suffixes have been obsoleted by a more useful, resolver-
based implementation of suffixing for partially-qualified domain names. The prior mechanisms could fail
HP-UX 11i Version 2: August 2003 − 4 − Hewlett-Packard Company Section 1M−−491