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host(1)                              BIND 9                              host(1)


       host - DNS lookup utility


       host [-aACdlnrsTUwv] [-c class] [-N ndots] [-p port] [-R number] [-t
       type] [-W wait] [-m flag] [ [-4] | [-6] ] [-v] [-V] {name} [server]


       host is a simple utility for performing DNS lookups. It is normally used
       to convert names to IP addresses and vice versa. When no arguments or
       options are given, host prints a short summary of its command-line
       arguments and options.

       name is the domain name that is to be looked up. It can also be a
       dotted-decimal IPv4 address or a colon-delimited IPv6 address, in which
       case host by default performs a reverse lookup for that address.  server
       is an optional argument which is either the name or IP address of the
       name server that host should query instead of the server or servers
       listed in /etc/resolv.conf.


       -4     This option specifies that only IPv4 should be used for query
              transport. See also the -6 option.

       -6     This option specifies that only IPv6 should be used for query
              transport. See also the -4 option.

       -a     The -a ("all") option is normally equivalent to -v -t ANY. It also
              affects the behavior of the -l list zone option.

       -A     The -A ("almost all") option is equivalent to -a, except that
              RRSIG, NSEC, and NSEC3 records are omitted from the output.

       -c class
              This option specifies the query class, which can be used to lookup
              HS (Hesiod) or CH (Chaosnet) class resource records. The default
              class is IN (Internet).

       -C     This option indicates that named should check consistency, meaning
              that host queries the SOA records for zone name from all the
              listed authoritative name servers for that zone. The list of name
              servers is defined by the NS records that are found for the zone.

       -d     This option prints debugging traces, and is equivalent to the -v
              verbose option.

       -l     This option tells named to list the zone, meaning the host command
              performs a zone transfer of zone name and prints out the NS, PTR,
              and address records (A/AAAA).

              Together, the -l -a options print all records in the zone.

       -N ndots
              This option specifies the number of dots (ndots) that have to be
              in name for it to be considered absolute. The default value is
              that defined using the ndots statement in /etc/resolv.conf, or 1
              if no ndots statement is present. Names with fewer dots are
              interpreted as relative names, and are searched for in the domains
              listed in the search or domain directive in /etc/resolv.conf.

       -p port
              This option specifies the port to query on the server. The default
              is 53.

       -r     This option specifies a non-recursive query; setting this option
              clears the RD (recursion desired) bit in the query. This means
              that the name server receiving the query does not attempt to
              resolve name. The -r option enables host to mimic the behavior of
              a name server by making non-recursive queries, and expecting to
              receive answers to those queries that can be referrals to other
              name servers.

       -R number
              This option specifies the number of retries for UDP queries. If
              number is negative or zero, the number of retries is silently set
              to 1. The default value is 1, or the value of the attempts option
              in /etc/resolv.conf, if set.

       -s     This option tells named not to send the query to the next
              nameserver if any server responds with a SERVFAIL response, which
              is the reverse of normal stub resolver behavior.

       -t type
              This option specifies the query type. The type argument can be any
              recognized query type: CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc.

              When no query type is specified, host automatically selects an
              appropriate query type. By default, it looks for A, AAAA, and MX
              records. If the -C option is given, queries are made for SOA
              records. If name is a dotted-decimal IPv4 address or
              colon-delimited IPv6 address, host queries for PTR records.

              If a query type of IXFR is chosen, the starting serial number can
              be specified by appending an equals sign (=), followed by the
              starting serial number, e.g., -t IXFR=12345678.

       -T, -U This option specifies TCP or UDP. By default, host uses UDP when
              making queries; the -T option makes it use a TCP connection when
              querying the name server. TCP is automatically selected for
              queries that require it, such as zone transfer (AXFR) requests.
              Type ANY queries default to TCP, but can be forced to use UDP
              initially via -U.

       -m flag
              This option sets memory usage debugging: the flag can be record,
              usage, or trace. The -m option can be specified more than once to
              set multiple flags.

       -v     This option sets verbose output, and is equivalent to the -d debug
              option. Verbose output can also be enabled by setting the debug
              option in /etc/resolv.conf.

       -V     This option prints the version number and exits.

       -w     This option sets "wait forever": the query timeout is set to the
              maximum possible. See also the -W option.

       -W wait
              This options sets the length of the wait timeout, indicating that
              named should wait for up to wait seconds for a reply. If wait is
              less than 1, the wait interval is set to 1 second.

              By default, host waits for 5 seconds for UDP responses and 10
              seconds for TCP connections. These defaults can be overridden by
              the timeout option in /etc/resolv.conf.

              See also the -w option.


       If host has been built with IDN (internationalized domain name) support,
       it can accept and display non-ASCII domain names. host appropriately
       converts character encoding of a domain name before sending a request to
       a DNS server or displaying a reply from the server.  To turn off IDN
       support, define the IDN_DISABLE environment variable. IDN support is
       disabled if the variable is set when host runs.




       dig(1), named(8).


       Internet Systems Consortium


       2023, Internet Systems Consortium

9.18.12                            2023-02-03                            host(1)

bind 9.18.12 - Generated Sat Feb 18 08:16:14 CST 2023
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