1NAMED(8)                             BIND9                            NAMED(8)


6       named - Internet domain name server


9       named [[-4] | [-6]] [-c config-file] [-d debug-level] [-D string]
10             [-E engine-name] [-f] [-g] [-L logfile] [-M option] [-m flag]
11             [-n #cpus] [-p port] [-s] [-S #max-socks] [-t directory]
12             [-U #listeners] [-u user] [-v] [-V] [-X lock-file]
13             [-x cache-file]


16       named is a Domain Name System (DNS) server, part of the BIND 9
17       distribution from ISC. For more information on the DNS, see RFCs 1033,
18       1034, and 1035.
20       When invoked without arguments, named will read the default
21       configuration file /etc/named.conf, read any initial data, and listen
22       for queries.


25       -4
26           Use IPv4 only even if the host machine is capable of IPv6.  -4 and
27           -6 are mutually exclusive.
29       -6
30           Use IPv6 only even if the host machine is capable of IPv4.  -4 and
31           -6 are mutually exclusive.
33       -c config-file
34           Use config-file as the configuration file instead of the default,
35           /etc/named.conf. To ensure that reloading the configuration file
36           continues to work after the server has changed its working
37           directory due to to a possible directory option in the
38           configuration file, config-file should be an absolute pathname.
40       -d debug-level
41           Set the daemon's debug level to debug-level. Debugging traces from
42           named become more verbose as the debug level increases.
44       -D string
45           Specifies a string that is used to identify a instance of named in
46           a process listing. The contents of string are not examined.
48       -E engine-name
49           When applicable, specifies the hardware to use for cryptographic
50           operations, such as a secure key store used for signing.
52           When BIND is built with OpenSSL PKCS#11 support, this defaults to
53           the string "pkcs11", which identifies an OpenSSL engine that can
54           drive a cryptographic accelerator or hardware service module. When
55           BIND is built with native PKCS#11 cryptography
56           (--enable-native-pkcs11), it defaults to the path of the PKCS#11
57           provider library specified via "--with-pkcs11".
59       -f
60           Run the server in the foreground (i.e. do not daemonize).
62       -g
63           Run the server in the foreground and force all logging to stderr.
65       -L logfile
66           Log to the file logfile by default instead of the system log.
68       -M option
69           Sets the default memory context options. Currently the only
70           supported option is external, which causes the internal memory
71           manager to be bypassed in favor of system-provided memory
72           allocation functions.
74       -m flag
75           Turn on memory usage debugging flags. Possible flags are usage,
76           trace, record, size, and mctx. These correspond to the
77           ISC_MEM_DEBUGXXXX flags described in <isc/mem.h>.
79       -n #cpus
80           Create #cpus worker threads to take advantage of multiple CPUs. If
81           not specified, named will try to determine the number of CPUs
82           present and create one thread per CPU. If it is unable to determine
83           the number of CPUs, a single worker thread will be created.
85       -p port
86           Listen for queries on port port. If not specified, the default is
87           port 53.
89       -s
90           Write memory usage statistics to stdout on exit.
92               Note
93               This option is mainly of interest to BIND 9 developers and may
94               be removed or changed in a future release.
96       -S #max-socks
97           Allow named to use up to #max-socks sockets. The default value is
98           4096 on systems built with default configuration options, and 21000
99           on systems built with "configure --with-tuning=large".
101               Warning
102               This option should be unnecessary for the vast majority of
103               users. The use of this option could even be harmful because the
104               specified value may exceed the limitation of the underlying
105               system API. It is therefore set only when the default
106               configuration causes exhaustion of file descriptors and the
107               operational environment is known to support the specified
108               number of sockets. Note also that the actual maximum number is
109               normally a little fewer than the specified value because named
110               reserves some file descriptors for its internal use.
112       -t directory
113           Chroot to directory after processing the command line arguments,
114           but before reading the configuration file.
116               Warning
117               This option should be used in conjunction with the -u option,
118               as chrooting a process running as root doesn't enhance security
119               on most systems; the way chroot(2) is defined allows a process
120               with root privileges to escape a chroot jail.
122       -U #listeners
123           Use #listeners worker threads to listen for incoming UDP packets on
124           each address. If not specified, named will calculate a default
125           value based on the number of detected CPUs: 1 for 1 CPU, and the
126           number of detected CPUs minus one for machines with more than 1
127           CPU. This cannot be increased to a value higher than the number of
128           CPUs. If -n has been set to a higher value than the number of
129           detected CPUs, then -U may be increased as high as that value, but
130           no higher. On Windows, the number of UDP listeners is hardwired to
131           1 and this option has no effect.
133       -u user
134           Setuid to user after completing privileged operations, such as
135           creating sockets that listen on privileged ports.
137               Note
138               On Linux, named uses the kernel's capability mechanism to drop
139               all root privileges except the ability to bind(2) to a
140               privileged port and set process resource limits. Unfortunately,
141               this means that the -u option only works when named is run on
142               kernel 2.2.18 or later, or kernel 2.3.99-pre3 or later, since
143               previous kernels did not allow privileges to be retained after
144               setuid(2).
146       -v
147           Report the version number and exit.
149       -V
150           Report the version number and build options, and exit.
152       -X lock-file
153           Acquire a lock on the specified file at runtime; this helps to
154           prevent duplicate named instances from running simultaneously. Use
155           of this option overrides the lock-file option in named.conf. If set
156           to none, the lock file check is disabled.
158       -x cache-file
159           Load data from cache-file into the cache of the default view.
161               Warning
162               This option must not be used. It is only of interest to BIND 9
163               developers and may be removed or changed in a future release.


166       In routine operation, signals should not be used to control the
167       nameserver; rndc should be used instead.
169       SIGHUP
170           Force a reload of the server.
173           Shut down the server.
175       The result of sending any other signals to the server is undefined.


178       The named configuration file is too complex to describe in detail here.
179       A complete description is provided in the BIND 9 Administrator
180       Reference Manual.
182       named inherits the umask (file creation mode mask) from the parent
183       process. If files created by named, such as journal files, need to have
184       custom permissions, the umask should be set explicitly in the script
185       used to start the named process.


188       /etc/named.conf
189           The default configuration file.
191       /var/run/named/named.pid
192           The default process-id file.


195       Red Hat SELinux BIND Security Profile:
197       By default, Red Hat ships BIND with the most secure SELinux policy that
198       will not prevent normal BIND operation and will prevent exploitation of
199       all known BIND security vulnerabilities . See the selinux(8) man page
200       for information about SElinux.
202       It is not necessary to run named in a chroot environment if the Red Hat
203       SELinux policy for named is enabled. When enabled, this policy is far
204       more secure than a chroot environment. Users are recommended to enable
205       SELinux and remove the bind-chroot package.
207       With this extra security comes some restrictions:
209       By default, the SELinux policy does not allow named to write any master
210       zone database files. Only the root user may create files in the
211       $ROOTDIR/var/named zone database file directory (the options {
212       "directory" } option), where $ROOTDIR is set in /etc/sysconfig/named.
214       The "named" group must be granted read privelege to these files in
215       order for named to be enabled to read them.
217       Any file created in the zone database file directory is automatically
218       assigned the SELinux file context named_zone_t .
220       By default, SELinux prevents any role from modifying named_zone_t
221       files; this means that files in the zone database directory cannot be
222       modified by dynamic DNS (DDNS) updates or zone transfers.
224       The Red Hat BIND distribution and SELinux policy creates three
225       directories where named is allowed to create and modify files:
226       /var/named/slaves, /var/named/dynamic /var/named/data. By placing files
227       you want named to modify, such as slave or DDNS updateable zone files
228       and database / statistics dump files in these directories, named will
229       work normally and no further operator action is required. Files in
230       these directories are automatically assigned the 'named_cache_t' file
231       context, which SELinux allows named to write.
233       Red Hat BIND SDB support:
235       Red Hat ships named with compiled in Simplified Database Backend
236       modules that ISC provides in the "contrib/sdb" directory. Install bind-
237       sdb package if you want use them
239       The SDB modules for LDAP, PostGreSQL, DirDB and SQLite are compiled
240       into named-sdb.
242       See the documentation for the various SDB modules in
243       /usr/share/doc/bind-sdb-*/ .


246       RFC 1033, RFC 1034, RFC 1035, named-checkconf(8), named-checkzone(8),
247       rndc(8), lwresd(8), named.conf(5), BIND 9 Administrator Reference
248       Manual.


251       Internet Systems Consortium, Inc.
254       Copyright © 2000, 2001, 2003-2009, 2011, 2013-2018 Internet Systems
255       Consortium, Inc. ("ISC")
259ISC                               2014-02-19                          NAMED(8)