Defines a default directory used for all subsequent file references
anywhere in the
is forced to
dump memory, the memory dump is stored in this directory.
Declares the local name server as the primary master server for the
domain specified by
. As a primary server, the system
loads the name server database from the local disk file specified by
domain-name server-address-list file-name
Makes the local server a secondary master server for the domain identified
contains the IP
address of at least one other master server for this domain. Multiple
addresses can be provided in the list, but at least the primary server's
address should be provided. The local server will try each server in
the list until it successfully loads the name server database. The local
server transfers the entire domain database and stores all of the data it
receives in a local file identified by
. After completing
the transfer, the local server answers all queries for information about
the domain with complete authority.
command points to the file used to initialize the name server
cache with a list of root servers. This command starts with the keyword
, followed by the name of the root domain (.), and ends with
the name of the file that contains the root server list. This file can
have any name you wish, but it is usually called
command is included in
needs the list of root
servers as a starting point from which to locate all other DNS
server-address server-address ...
with a list of
servers to try if it can't resolve a query from its own cache. In the
is the IP address of a server on
your network that can perform a recursive name server query for the
local host. (A recursive query
means that the remote server pursues
the answer to the query, even if it does not have the answer itself,
and returns the answer to the originator.) The servers listed on the
command line (the servers are also called
"forwarders") are tried in order until one responds to the query. The
listed servers develop an extensive cache that benefits every host
that uses them. Because of this, their use is often recommended. If
you plan to use
, your network administrator should
define the list of forwarders for your network. The forwarders only
develop a rich cache if they are used by several hosts.
command forces the local server to use only the
servers listed on the forwarders command line. The slave command can
only be used if a
command is also present in the
file. A server that has a
command in its
file is called a
. A slave server
does not attempt to contact the authoritative servers for a domain,
even if the forwarding servers do not respond to its query. Regardless
of the circumstances, a slave server queries only the forwarders. The
command is used when limited network access makes the
forwarders the only servers that can be reached by the local host. The
command is not used on systems that have full Internet
access because it limits their flexibility.
network network ...
to prefer addresses from
the listed networks over addresses from other networks. Normally, DNS
sorts the addresses in a response only if the host issuing the query
and the name server share a network. In that case, the shared network
is the preferred network.
command limits zone transfers to hosts with the specified
is written in dotted decimal notation
and is intepreted as a network address. The optional mask field
is used to change the interpretation of the
. When a bit
is on in the mask field, that bit is significant for determining which
hosts will be allowed to receive a zone file transfer. For example,
allows every host on network 172.16 to do zone
file transfers, while
zone file transfers to the single host 172.16.12.3.
For security reasons, many sites do not want to let everyone list
all of the hostnames in their domain.
limits the ability to
retrieve your entire domain to specific, trusted hosts.
an alternative form of this command maintained for compatibility with
older server implementations.
command includes the contents of
at the location
that the command appears in the boot file. This command can be used
for very large configurations that are maintained by different people.
address address ...
command prevents queries from being sent to the name server
must be an IP address, not
a domain name. This command is used to avoid cache contamination when
you know that a remote name server is providing incorrect informatiom.
is only a temporary fix placed in the boot file until the remote
domain administrator has a chance to fix the real problem.
command changes BIND's internal quotas.
is a number that specifies the new quota setting.
, for kilobytes, megabytes, and gigabytes, respectively, can be
appended to the new quota value number as appropriate.
the name of the quota being set. There are four possible values for
sets the process data size quota;
sets the number of named transfer subprocesses that BIND
may spawn at any one time;
sets the maximum number
of simultaneous zone transfers allowed to any one remote nameserver.
There can be multiple limit commands in a boot file - one for each quota
that is being set.
option option ...
command enables optional features of BIND. The
keywords are Booleans. Specifying an
on the command line
turns on the optional behavior. By default, the optional features
are turned off. Valid
- logs all
queries via syslogd, which produces a very large amount of log
- all queries are to be sent to the forwarders;
this is exactly the same as the
command, though this syntax is now
preferred over the
- the nameserver
responds to inverse
queries with a fake reply rather than an error; used if you have some
clients that cannot properly handle the error.
name server answers a query for data only in a zone for which it
is authoritative; all other queries are answered with a referral to
nameserver does not fetch missing glue records for a query response;
the resulting response could be incomplete; it is
to limit cache growth and reduce the
chance of cache corruption.
command tells the name server to check host
names against the standards for hostnames defined in RFC 952, and to
check non-hostname responses to make sure that they contain nothing
but printable characters. The
is the source of the
hostname or string data that is being checked. The
for the primary zone file;
secondary zone file, or
for the message received during
recursive search. The
tells the name server what to do
when an error is detected:
(reject the data; do not load,
cache, or forward it);
(send an error message to the system
(process the data as if no error occurred).
commands can appear in a boot file; one for
each source of data. The action for each source can be different.
command performs exactly the same function as the
limit transfers-in command described previously. The
command is now the preferred syntax.