1NAMED(8) BIND9 NAMED(8)
2
6 named - Internet domain name server
7
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]
14
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.
19 When invoked without arguments, named will read the default
21 configuration file /etc/named.conf, read any initial data, and listen
22 for queries.
23
25 -4
26 Use IPv4 only even if the host machine is capable of IPv6. -4 and
27 -6 are mutually exclusive.
28 -6
30 Use IPv6 only even if the host machine is capable of IPv4. -4 and
31 -6 are mutually exclusive.
32 -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.
39 -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.
43 -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.
47 -E engine-name
49 When applicable, specifies the hardware to use for cryptographic
50 operations, such as a secure key store used for signing.
51 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".
58 -f
60 Run the server in the foreground (i.e. do not daemonize).
61 -g
63 Run the server in the foreground and force all logging to stderr.
64 -L logfile
66 Log to the file logfile by default instead of the system log.
67 -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.
73 -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>.
78 -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.
84 -p port
86 Listen for queries on port port. If not specified, the default is
87 port 53.
88 -s
90 Write memory usage statistics to stdout on exit.
91 Note
93 This option is mainly of interest to BIND 9 developers and may
94 be removed or changed in a future release.
95 -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".
100 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.
111 -t directory
113 Chroot to directory after processing the command line arguments,
114 but before reading the configuration file.
115 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.
121 -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.
132 -u user
134 Setuid to user after completing privileged operations, such as
135 creating sockets that listen on privileged ports.
136 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).
145 -v
147 Report the version number and exit.
148 -V
150 Report the version number and build options, and exit.
151 -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.
157 -x cache-file
159 Load data from cache-file into the cache of the default view.
160 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.
164
166 In routine operation, signals should not be used to control the
167 nameserver; rndc should be used instead.
168 SIGHUP
170 Force a reload of the server.
171 SIGINT, SIGTERM
173 Shut down the server.
174 The result of sending any other signals to the server is undefined.
176
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.
181 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.
186
188 /etc/named.conf
189 The default configuration file.
190 /var/run/named/named.pid
192 The default process-id file.
193
195 Red Hat SELinux BIND Security Profile:
196 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.
201 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.
206 With this extra security comes some restrictions:
208 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.
213 The "named" group must be granted read privelege to these files in
215 order for named to be enabled to read them.
216 Any file created in the zone database file directory is automatically
218 assigned the SELinux file context named_zone_t .
219 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.
223 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.
232 Red Hat BIND SDB support:
234 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
238 The SDB modules for LDAP, PostGreSQL, DirDB and SQLite are compiled
240 into named-sdb.
241 See the documentation for the various SDB modules in
243 /usr/share/doc/bind-sdb-*/ .
244 Red Hat system-config-bind:
246 Red Hat provides the system-config-bind GUI to configure named.conf and
248 zone database files. Run the "system-config-bind" command and access
249 the manual by selecting the Help menu.
250
252 RFC 1033, RFC 1034, RFC 1035, named-checkconf(8), named-checkzone(8),
253 rndc(8), lwresd(8), named.conf(5), BIND 9 Administrator Reference
254 Manual.
255
257 Internet Systems Consortium, Inc.
258
260 Copyright © 2000, 2001, 2003-2009, 2011, 2013-2019 Internet Systems
261 Consortium, Inc. ("ISC")
262ISC 2014-02-19 NAMED(8)