1NAMED(8)                            BIND 9                            NAMED(8)
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NAME

6       named - Internet domain name server
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SYNOPSIS

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

15       named is a Domain Name System (DNS) server, part of the BIND 9  distri‐
16       bution  from  ISC.  For  more information on the DNS, see RFC 1033, RFC
17       1034, and RFC 1035.
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19       When invoked without arguments, named reads the  default  configuration
20       file /etc/named.conf, reads any initial data, and listens for queries.
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OPTIONS

23       -4     This  option  tells named to use only IPv4, even if the host ma‐
24              chine is capable of IPv6. -4 and -6 are mutually exclusive.
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26       -6     This option tells named to use only IPv6, even if the  host  ma‐
27              chine is capable of IPv4. -4 and -6 are mutually exclusive.
28
29       -c config-file
30              This  option tells named to use config-file as its configuration
31              file instead of the default, /etc/named.conf. To ensure that the
32              configuration  file can be reloaded after the server has changed
33              its working directory due to to a possible directory  option  in
34              the  configuration file, config-file should be an absolute path‐
35              name.
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37       -d debug-level
38              This option sets the daemon's debug level to debug-level. Debug‐
39              ging  traces  from  named become more verbose as the debug level
40              increases.
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42       -D string
43              This option specifies a string that is used to  identify  a  in‐
44              stance of named in a process listing. The contents of string are
45              not examined.
46
47       -E engine-name
48              When applicable, this option specifies the hardware to  use  for
49              cryptographic  operations,  such  as a secure key store used for
50              signing.
51
52              When BIND 9 is built with OpenSSL, this needs to be set  to  the
53              OpenSSL engine identifier that drives the cryptographic acceler‐
54              ator or hardware service module (usually pkcs11). When  BIND  is
55              built with native PKCS#11 cryptography (--enable-native-pkcs11),
56              it defaults to the path of the PKCS#11 provider  library  speci‐
57              fied via --with-pkcs11.
58
59       -f     This option runs the server in the foreground (i.e., do not dae‐
60              monize).
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62       -g     This option runs the server in the  foreground  and  forces  all
63              logging to stderr.
64
65       -L logfile
66              This option sets the log to the file logfile by default, instead
67              of the system log.
68
69       -M option
70              This option sets the default memory context options. If  set  to
71              external,  the  internal  memory manager is bypassed in favor of
72              system-provided memory allocation functions.  If  set  to  fill,
73              blocks  of  memory  are filled with tag values when allocated or
74              freed, to assist debugging of memory problems.  nofill  disables
75              this behavior, and is the default unless named has been compiled
76              with developer options.
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78       -m flag
79              This option turns on  memory  usage  debugging  flags.  Possible
80              flags are usage, trace, record, size, and mctx. These correspond
81              to the ISC_MEM_DEBUGXXXX flags described in <isc/mem.h>.
82
83       -n #cpus
84              This option creates #cpus worker threads to  take  advantage  of
85              multiple  CPUs.  If  not specified, named tries to determine the
86              number of CPUs present and creates one thread per CPU. If it  is
87              unable  to  determine the number of CPUs, a single worker thread
88              is created.
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90       -p port
91              This option listens for queries on port. If not  specified,  the
92              default is port 53.
93
94       -s     This option writes memory usage statistics to stdout on exit.
95
96       NOTE:
97          This  option  is  mainly of interest to BIND 9 developers and may be
98          removed or changed in a future release.
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100       -S #max-socks
101              This option allows named to use up to  #max-socks  sockets.  The
102              default  value is 21000 on systems built with default configura‐
103              tion  options,  and  4096  on  systems  built   with   configure
104              --with-tuning=small.
105
106       WARNING:
107          This  option  should  be unnecessary for the vast majority of users.
108          The use of this option could even be harmful, because the  specified
109          value  may exceed the limitation of the underlying system API. It is
110          therefore set only when the default configuration causes  exhaustion
111          of file descriptors and the operational environment is known to sup‐
112          port the specified number of sockets. Note also that the actual max‐
113          imum number is normally slightly fewer than the specified value, be‐
114          cause named reserves some file descriptors for its internal use.
115
116       -t directory
117              This option tells named to chroot to directory after  processing
118              the command-line arguments, but before reading the configuration
119              file.
120
121       WARNING:
122          This option should be used in conjunction with the -u option, as ch‐
123          rooting  a  process running as root doesn't enhance security on most
124          systems; the way chroot is defined allows a process with root privi‐
125          leges to escape a chroot jail.
126
127       -U #listeners
128              This  option tells named the number of #listeners worker threads
129              to listen on, for incoming UDP packets on each address.  If  not
130              specified,  named calculates a default value based on the number
131              of detected CPUs: 1 for 1 CPU, and the number of  detected  CPUs
132              minus one for machines with more than 1 CPU.  This cannot be in‐
133              creased to a value higher than the number of CPUs.   If  -n  has
134              been  set  to  a  higher value than the number of detected CPUs,
135              then -U may be increased as high as that value, but  no  higher.
136              On  Windows,  the  number of UDP listeners is hardwired to 1 and
137              this option has no effect.
138
139       -u user
140              This option sets the setuid to user after completing  privileged
141              operations,  such  as creating sockets that listen on privileged
142              ports.
143
144       NOTE:
145          On Linux, named uses the kernel's capability mechanism to  drop  all
146          root  privileges except the ability to bind to a privileged port and
147          set process resource limits. Unfortunately, this means that  the  -u
148          option  only  works  when named is run on kernel 2.2.18 or later, or
149          kernel 2.3.99-pre3 or later, since previous kernels  did  not  allow
150          privileges to be retained after setuid.
151
152       -v     This option reports the version number and exits.
153
154       -V     This  option  reports  the version number and build options, and
155              exits.
156
157       -X lock-file
158              This option acquires a lock on the specified  file  at  runtime;
159              this helps to prevent duplicate named instances from running si‐
160              multaneously.  Use of this option overrides the lock-file option
161              in named.conf. If set to none, the lock file check is disabled.
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163       -x cache-file
164              This option loads data from cache-file into the cache of the de‐
165              fault view.
166
167       WARNING:
168          This option must not be used in normal operations. It is only of in‐
169          terest  to  BIND 9 developers and may be removed or changed in a fu‐
170          ture release.
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SIGNALS

173       In routine operation, signals should not be used to control  the  name‐
174       server; rndc should be used instead.
175
176       SIGHUP This signal forces a reload of the server.
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178       SIGINT, SIGTERM
179              These signals shut down the server.
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181       The result of sending any other signals to the server is undefined.
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CONFIGURATION

184       The named configuration file is too complex to describe in detail here.
185       A complete description is provided in the BIND 9  Administrator  Refer‐
186       ence Manual.
187
188       named  inherits  the  umask  (file  creation mode mask) from the parent
189       process. If files created by named, such as journal files, need to have
190       custom  permissions,  the  umask should be set explicitly in the script
191       used to start the named process.
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FILES

194       /etc/named.conf
195              The default configuration file.
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197       /var/run/named/named.pid
198              The default process-id file.
199

SEE ALSO

201       RFC 1033, RFC 1034, RFC 1035,  named-checkconf(8),  named-checkzone(8),
202       rndc(8), named.conf(5), BIND 9 Administrator Reference Manual.
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AUTHOR

205       Internet Systems Consortium
206
208       2021, Internet Systems Consortium
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2139.16.16-RH                                                            NAMED(8)
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