GNU/Linux man pages
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GNU/Linux |
CentOS 5.3 |
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named(8) |
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named − Internet domain name server
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named [−4] [−6] [−c config−file] [−d debug−level] [−f] [−g] [−n #cpus] [−p port] [−s] [−t directory] [−u user] [−v] [−x cache−file] [−D] |
named is a Domain Name System (DNS) server, part of the BIND 9 distribution from ISC. For more information on the DNS, see RFCs 1033, 1034, and 1035.
When invoked without arguments, named will read the default configuration file /etc/named.conf, read any initial data, and listen for queries.
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−4 |
Use IPv4 only even if the host machine is capable of IPv6. −4 and −6 are mutually exclusive. | ||
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−6 |
Use IPv6 only even if the host machine is capable of IPv4. −4 and −6 are mutually exclusive. |
−c config−file
Use config−file as the configuration file instead of the default, /etc/named.conf. To ensure that reloading the configuration file continues to work after the server has changed its working directory due to to a possible directory option in the configuration file, config−file should be an absolute pathname.
−d debug−level
Set the daemon’s debug level to debug−level. Debugging traces from named become more verbose as the debug level increases.
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−f |
Run the server in the foreground (i.e. do not daemonize). | ||
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−g |
Run the server in the foreground and force all logging to stderr. |
−n #cpus
Create #cpus worker threads to take advantage of multiple CPUs. If not specified, named will try to determine the number of CPUs present and create one thread per CPU. If it is unable to determine the number of CPUs, a single worker thread will be created.
−p port
Listen for queries on port port. If not specified, the default is port 53.
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−s |
Write memory usage statistics to stdout on exit. |
Note: This option is mainly of interest to BIND 9 developers and may be removed or changed in a future release.
−t directory
chroot() to
directory after processing the command line
arguments, but before reading the configuration file.
Warning: This option should be used in conjunction with
the −u option, as chrooting a process running
as root doesn’t enhance security on most systems; the
way chroot() is defined allows a process with root
privileges to escape a chroot jail.
−u user
setuid() to user
after completing privileged operations, such as creating
sockets that listen on privileged ports.
Note: On Linux, named uses the kernel’s
capability mechanism to drop all root privileges except the
ability to bind() to a privileged port and set
process resource limits. Unfortunately, this means that the
−u option only works when named is run
on kernel 2.2.18 or later, or kernel 2.3.99−pre3 or
later, since previous kernels did not allow privileges to be
retained after setuid().
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−v |
Report the version number and exit. |
−x cache−file
Load data from
cache−file into the cache of the default view.
Warning: This option must not be used. It is only of
interest to BIND 9 developers and may be removed or changed
in a future release.
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−D |
Enable dynamic management of the forwarding table with D-BUS messages. This option is required for Red Hat NetworkManager support. See doc/README.DBUS . |
In routine
operation, signals should not be used to control the
nameserver; rndc should be used instead.
SIGHUP
Force a reload of the server.
SIGINT, SIGTERM
Shut down the server.
The result of sending any other signals to the server is undefined.
The named configuration file is too complex to describe in detail here. A complete description is provided in the BIND 9 Administrator Reference Manual.
Red Hat SELinux BIND Security Profile:
By default, Red Hat ships BIND with the most secure SELinux policy that will not prevent normal BIND operation and will prevent exploitation of all known BIND security vulnerabilities . See the selinux(8) man page for information about SElinux.
It is not necessary to run named in a chroot environment if the Red Hat SELinux policy for named is enabled. When enabled, this policy is far more secure than a chroot environment.
With this extra
security comes some restrictions:
By default, the SELinux policy does not allow named to write
any master zone database files. Only the root user may
create files in the $ROOTDIR/var/named zone database file
directory (the options { "directory" } option),
where $ROOTDIR is set in /etc/sysconfig/named.
The "named" group must be granted read privelege
to these files in order for named to be enabled to read
them.
Any file created in the zone database file directory is
automatically assigned the SELinux file context named_zone_t
.
By default, SELinux prevents any role from modifying
named_zone_t files; this means that files in the zone
database directory cannot be modified by dynamic DNS (DDNS)
updates or zone transfers.
The Red Hat BIND distribution and SELinux policy creates two
directories where named is allowed to create and modify
files: $ROOTDIR/var/named/slaves and
$ROOTDIR/var/named/data. By placing files you want named to
modify, such as slave or DDNS updateable zone files and
database / statistics dump files in these directories, named
will work normally and no further operator action is
required. Files in these directories are automatically
assigned the ’named_cache_t’ file context, which
SELinux allows named to write.
You can enable the named_t domain to write and create
named_zone_t files by use of the SELinux tunable boolean
variable "named_write_master_zones", using the
setsebool(8) command or the system-config-security GUI . If
you do this, you must also set the ENABLE_ZONE_WRITE
variable in /etc/sysconfig/named to 1 / yes to set the
ownership of files in the $ROOTDIR/var/named directory to
named:named in order for named to be allowed to write
them.
Red Hat BIND named_sdb SDB support:
Red Hat ships
the bind-sdb RPM that provides the /usr/sbin/named_sdb
program, which is named compiled with the Simplified
Database Backend modules that ISC provides in the
"contrib/sdb" directory.
The SDB modules for LDAP, PostGreSQL and DirDB are compiled
into named_sdb.
To run named_sdb, set the ENABLE_SDB variable in
/etc/sysconfig/named to 1 or "yes", and then the
"service named start" named initscript will run
named_sdb instead of named .
See the documentation for the various SDB modules in
/usr/share/doc/bind-sdb-*/ .
Red Hat system-config-bind:
Red Hat provides the system-config-bind GUI to configure named.conf and zone database files. Run the "system-config-bind" command and access the manual by selecting the Help menu.
/etc/named.conf
The default configuration file.
/var/run/named.pid
The default process−id file.
RFC 1033, RFC 1034, RFC 1035, rndc(8), lwresd(8), named.conf(5), BIND 9 Administrator Reference Manual.
Internet Systems Consortium
Copyright © 2004−2006 Internet Systems Consortium, Inc. ("ISC")
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named(8) | |