System Administration Commands host(1M)
NAME
host - DNS lookup utility
SYNOPSIS
host [-aCdilrTvw] [-c class] [-N ndots] [-R number]
[-t type] [-W wait] [-4 -6] `aname [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 arguments 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
(Internet).
-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.
SunOS 5.11 Last change: 24 Dec 2008 1
System Administration Commands host(1M)
-d Generate verbose output. This option is
equivalent to -v. These two options are pro-
vided for backward compatibility. In previous
versions, 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/A). If combined
with -a, all records will be displayed. The
argument is provided for compatibility with
previous implementations. Options -la is
equivalent to making a query of type AXFR.
-N ndots Set the number of dots 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 inter-
preted 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.
SunOS 5.11 Last change: 24 Dec 2008 2
System Administration Commands host(1M)
-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
appropriate query type. By default it looks for
A, A, 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-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
equal followed by the starting serial number
(for example: -t IXFR=12345678).
-T Use a TCP connection when querying the name
server. TCP is automatically 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
ATRIBUTES
See for descriptions of the following attributes:
SunOS 5.11 Last change: 24 Dec 2008 3
System Administration Commands host(1M)
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWbind
Interface Stability External
SEE ALSO
dig(1M), named(1M), attributes(5)
RFC 1035, RFC 1886, RFC 3152
SunOS 5.11 Last change: 24 Dec 2008 4
|
