1host(1M) System Administration Commands host(1M)
2
6 host - DNS lookup utility
7
9 host [-aCdilrTvw] [-c class] [-N ndots] [-R number]
10 [-t type] [-W wait] [-4 | -6] `aname [server]
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14 The host utility performs simple DNS lookups. It is normally used to
15 convert names to IP addresses and IP addresses to names. When no argu‐
16 ments or options are given, host prints a short summary of its command
17 line arguments and options.
18 The name argument is the domain name that is to be looked up. It can
21 also be a dotted-decimal IPv4 address or a colon-delimited IPv6
22 address, in which case host by default performs a reverse lookup for
23 that address. The optional server argument is either the name or IP
24 address of the name server that host should query instead of the server
25 or servers listed in /etc/resolv.conf.
26
28 The following options are supported:
29 -4 Use only IPv4 transport. By default, both IPv4 and IPv6
31 transports can be used. Options -4 and -6 are mutually
32 exclusive.
33 -6 Use only IPv6 transport. By default, both IPv4 and IPv6
36 transports can be used. Options -4 and -6 are mutually
37 exclusive.
38 -a Equivalent to setting the -v option and asking host to
41 make a query of type ANY.
42 -c class Make a DNS query of class class. This can be used to
45 lookup Hesiod or Chaosnet class resource records. The
46 default class is IN (Internet).
47 -C Attempt to display the SOA records for zone name from all
50 the listed authoritative name servers for that zone. The
51 list of name servers is defined by the NS records that are
52 found for the zone.
53 -d Generate verbose output. This option is equivalent to -v.
56 These two options are provided for backward compatibility.
57 In previous versions, the -d option switched on debugging
58 traces and -v enabled verbose output.
59 -i Specifies that reverse lookups of IPv6 addresses should
62 use the IP6.INT domain as defined in RFC 1886. The default
63 is to use RFC 3152 domain IP6.ARPA.
64 -l List mode. This option makes host perform a zone transfer
67 for zone name, displaying the NS, PTR and address records
68 (A/AAAA). If combined with -a, all records will be dis‐
69 played. The argument is provided for compatibility with
70 previous implementations. Options -la is equivalent to
71 making a query of type AXFR.
72 -N ndots Set the number of dots that have to be in name for it to
75 be considered absolute. The default value is that defined
76 using the ndots statement in /etc/resolv.conf, or 1 if no
77 ndots statement is present. Names with fewer dots are
78 interpreted as relative names and will be searched for in
79 the domains listed in the search or domain directive in
80 /etc/resolv.conf.
81 -r Make a non-recursive query. Setting this option clears the
84 RD (recursion desired) bit in the query made by host. The
85 name server receiving the query does not attempt to
86 resolve name. The -r option enables host to mimic the be‐
87 haviour of a name server by making non-recursive queries
88 and expecting to receive answers to those queries that are
89 usually referrals to other name servers.
90 -R number Change the number of UDP retries for a lookup. The number
93 argument indicates how many times host will repeat a query
94 that does not get answered. The default number of retries
95 is 1. If number is negative or zero, the number of retries
96 will default to 1.
97 -t type Select the query type. The type argument can be any recog‐
100 nised query type: CNAME, NS, SOA, SIG, KEY, and AXFR,
101 among others. When no query type is specified, host auto‐
102 matically selects an appropriate query type. By default it
103 looks for A, AAAA, and MX records, but if the -C option is
104 specified, queries are made for SOA records. If name is a
105 dotted-decimal IPv4 address or colon-delimited IPv6
106 address, host queries for PTR records.
107 If a query type of IXFR is chosen the starting serial num‐
109 ber can be specified by appending an equal followed by the
110 starting serial number (for example: -t IXFR=12345678).
111 -T Use a TCP connection when querying the name server. TCP is
114 automatically selected for queries that require it, such
115 as zone transfer (AXFR) requests. By default host uses UDP
116 when making queries.
117 -v Generate verbose output. This option is equivalent to -d.
120 -w Wait forever for a reply. The time to wait for a response
123 will be set to the number of seconds given by the hard‐
124 ware's maximum value for an integer quantity.
125 -W wait Wait for wait seconds for a reply. If wait is less than
128 one, the wait interval is set to one second.
129
132 /etc/resolv.conf Resolver configuration file
133
136 See for descriptions of the following attributes:
137 ┌─────────────────────────────┬─────────────────────────────┐
142 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
143 ├─────────────────────────────┼─────────────────────────────┤
144 │Availability │SUNWbind │
145 ├─────────────────────────────┼─────────────────────────────┤
146 │Interface Stability │External │
147 └─────────────────────────────┴─────────────────────────────┘
148
150 dig(1M), named(1M), attributes(5)
151 RFC 1035, RFC 1886, RFC 3152
154SunOS 5.11 24 Dec 2008 host(1M)