NSD(8)                             NSD 4.3.8                            NSD(8)



NAME
       nsd - Name Server Daemon (NSD) version 4.3.8.

SYNOPSIS
       nsd [-4] [-6] [-a ip-address[@port]] [-c configfile] [-d] [-f database]
       [-h] [-i identity] [-I nsid] [-l logfile] [-N server-count] [-n noncur-
       rent-tcp-count]  [-P pidfile] [-p port] [-s seconds] [-t chrootdir] [-u
       username] [-V level] [-v]

DESCRIPTION
       NSD is a complete implementation of an  authoritative  DNS  nameserver.
       Upon startup, NSD will read the database specified with -f database ar-
       gument and put itself into background and answers queries on port 53 or
       a different port specified with -p port option. The database is created
       if it does not exist. By default, NSD will bind to all local interfaces
       available. Use the -a ip-address[@port] option to specify a single par-
       ticular interface address to be bound. If this  option  is  given  more
       than  once,  NSD will bind its UDP and TCP sockets to all the specified
       ip-addresses separately. If IPv6 is enabled when  NSD  is  compiled  an
       IPv6 address can also be specified.

OPTIONS
       All  the options can be specified in the configfile ( -c argument), ex-
       cept for the -v and -h options. If options are specified on the comman-
       dline,  the options on the commandline take precedence over the options
       in the configfile.

       Normally NSD should be started with the `nsd-control(8) start`  command
       invoked from a /etc/rc.d/nsd.sh script or similar at the operating sys-
       tem startup.

       -4     Only listen to IPv4 connections.

       -6     Only listen to IPv6 connections.

       -a ip-address[@port]
              Listen to the specified  ip-address.   The  ip-address  must  be
              specified in numeric format (using the standard IPv4 or IPv6 no-
              tation). Optionally, a port number can be given.  This flag  can
              be  specified multiple times to listen to multiple IP addresses.
              If this flag is not specified, NSD listens to the  wildcard  in-
              terface.

       -c configfile
              Read    specified    configfile    instead    of   the   default
              /etc/nsd/nsd.conf.  For format description see nsd.conf(5).

       -d     Do not fork, stay in the foreground.

       -f database
              Use  the  specified  database  instead   of   the   default   of
              '/var/db/nsd/nsd.db'.  If a zonesdir: is specified in the config
              file this path can be relative to that directory.

       -h     Print help information and exit.

       -i identity
              Return the specified identity when asked for  CH  TXT  ID.SERVER
              (This  option is used to determine which server is answering the
              queries when they are anycast). The default is the name returned
              by gethostname(3).

       -I nsid
              Add  the  specified  nsid to the EDNS section of the answer when
              queried with an NSID EDNS enabled packet.  As a sequence of  hex
              characters or with ascii_ prefix and then an ascii string.

       -l logfile
              Log messages to the specified logfile.  The default is to log to
              stderr and syslog. If a zonesdir: is  specified  in  the  config
              file this path can be relative to that directory.

       -N count
              Start  count NSD servers. The default is 1. Starting more than a
              single server is only useful  on  machines  with  multiple  CPUs
              and/or network adapters.

       -n number
              The maximum number of concurrent TCP connection that can be han-
              dled by each server. The default is 100.

       -P pidfile
              Use the specified pidfile instead of the platform  specific  de-
              fault,  which  is  mostly  /var/run/nsd.pid.   If a zonesdir: is
              specified in the config file, this path can be relative to  that
              directory.

       -p port
              Answer the queries on the specified port.  Normally this is port
              53.

       -s seconds
              Produce statistics dump every seconds seconds. This is equal  to
              sending SIGUSR1 to the daemon periodically.

       -t chroot
              Specifies a directory to chroot to upon startup. This option re-
              quires you to ensure that appropriate  syslogd(8)  socket  (e.g.
              chrootdir  /dev/log)  is  available, otherwise NSD won't produce
              any log output.

       -u username
              Drop user and group privileges to those of username after  bind-
              ing  the  socket.  The username must be one of: username, id, or
              id.gid. For example: nsd, 80, or 80.80.

       -V level
              This value specifies the verbosity level  for  (non-debug)  log-
              ging.  Default is 0.

       -v     Print the version number of NSD to standard error and exit.

       NSD reacts to the following signals:

       SIGTERM
              Stop answering queries, shutdown, and exit normally.

       SIGHUP Reload.   Scans zone files and if changed (mtime) reads them in.
              Also reopens the logfile (assists logrotation).

       SIGUSR1
              Dump BIND8-style statistics into the log. Ignored otherwise.

FILES
       "/var/db/nsd/nsd.db"
              default NSD database

       /var/run/nsd.pid
              the process id of the name server.

       /etc/nsd/nsd.conf
              default NSD configuration file

DIAGNOSTICS
       NSD will log all the problems via the standard syslog(8) daemon  facil-
       ity, unless the -d option is specified.

SEE ALSO
       nsd.conf(5), nsd-checkconf(8), nsd-control(8)

AUTHORS
       NSD was written by NLnet Labs and RIPE NCC joint team. Please see CRED-
       ITS file in the distribution for further details.



NLnet Labs                       Oct 12, 2021                           NSD(8)