host(1M) System Administration Commands host(1M)NAMEhost - DNS lookup utility
SYNOPSIShost [-aCdilmrsTvw] [-c class] [-N ndots] [-R number]
[-t type] [-W wait] [-4 | -6] name [server]
DESCRIPTION
The host utility performs simple DNS lookups. It is normally used to
convert names to IP addresses and IP addresses to names. When no argu‐
ments or options are given, host prints a short summary of its command
line arguments and options.
The name argument 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. The optional server argument 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.
OPTIONS
The following options are supported:
-4
Use only IPv4 transport. By default, both IPv4 and IPv6 transports
can be used. Options -4 and -6 are mutually exclusive.
-6
Use only IPv6 transport. By default, both IPv4 and IPv6 transports
can be used. Options -4 and -6 are mutually exclusive.
-a
Equivalent to setting the -v option and asking host to make a query
of type ANY.
-c class
Make a DNS query of class class. This can be used to lookup Hesiod
or Chaosnet class resource records. The default class is IN (Inter‐
net).
-C
Attempt to display 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
Generate verbose output. This option is equivalent to -v. These two
options are provided for backward compatibility. In previous ver‐
sions, the -d option switched on debugging traces and -v enabled
verbose output.
-i
Specifies that reverse lookups of IPv6 addresses should use the
IP6.INT domain as defined in RFC 1886. The default is to use RFC
3152 domain IP6.ARPA.
-l
List mode. This option makes host perform a zone transfer for zone
name, displaying the NS, PTR and address records (A/AAAA). If com‐
bined with -a, all records will be displayed. The argument is pro‐
vided for compatibility with previous implementations. Options -la
is equivalent to making a query of type AXFR.
-m
Sets the memory usage debugging flags: record, usage, and trace.
-N ndots
Set the number of dots that have to be in name for it to be consid‐
ered 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 will be searched for in the domains listed in the search or
domain directive in /etc/resolv.conf.
-r
Make a non-recursive query. Setting this option clears the RD
(recursion desired) bit in the query made by host. The name server
receiving the query does not attempt to resolve name. The -r option
enables host to mimic the behaviour of a name server by making non-
recursive queries and expecting to receive answers to those queries
that are usually referrals to other name servers.
-R number
Change the number of UDP retries for a lookup. The number argument
indicates how many times host will repeat a query that does not get
answered. The default number of retries is 1. If number is negative
or zero, the number of retries will default to 1.
-s
Specifies that the host not send the query to the next name server
if any server responds with a SERVFAIL response, which is the
reverse of normal stub resolver behavior.
-t type
Select the query type. The type argument can be any recognised
query type: CNAME, NS, SOA, SIG, KEY, and AXFR, among others. When
no query type is specified, host automatically selects an appropri‐
ate query type. By default it looks for A, AAAA, and MX records,
but if the -C option is specified, queries are made for SOA
records. If name is a dotted-decimal IPv4 address or colon-delim‐
ited 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 equal followed by the starting serial
number (for example: -t IXFR=12345678).
-T
Use a TCP connection when querying the name server. TCP is automat‐
ically selected for queries that require it, such as zone transfer
(AXFR) requests. By default host uses UDP when making queries.
-v
Generate verbose output. This option is equivalent to -d.
-w
Wait forever for a reply. The time to wait for a response will be
set to the number of seconds given by the hardware's maximum value
for an integer quantity.
-W wait
Wait for wait seconds for a reply. If wait is less than one, the
wait interval is set to one second.
FILES
/etc/resolv.conf
Resolver configuration file
ATTRIBUTES
See for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │network/dns/bind │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOdig(1M), named(1M), attributes(5)
RFC 1035, RFC 1886, RFC 3152
See the BIND 9 Administrator's Reference Manual. As of the date of pub‐
lication of this man page, this document is available at
https://www.isc.org/software/bind/documentation.
SunOS 5.10 11 Jan 2010 host(1M)
