HP-UX Reference (11i v1 05/09) - 1 User Commands A-M (vol 1)

h
host(1) host(1)
NAME
host - DNS lookup utility
SYNOPSIS
host [-aCdlnrTwv][-c class][
-N ndots][-R number][-t type][-W wait] name server
DESCRIPTION
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.
Arguments
name This 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 will by default perform a
reverse lookup for that address.
server This 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
.
Options
a This option is equivalent to setting the v option and asking host to make a query of type
ANY.
C When this option is used, host will 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.
c class This option instructs host to make a DNS query of class class. This can be used to lookup
Hesiod or Chaosnet class resource records. The default class is IN, for Internet.
dv Verbose output is generated by host when one of these options are used. The two options
are equivalent. They have been provided for backwards compatibility. In previous ver-
sions, the
d option switched on debugging traces and v enabled verbose output.
l List mode is selected by this option. This makes host perform a zone transfer for zone
name. The argument is provided for compatibility with older implemementations. This
option is equivalent to making a query of type
AXFR.
n This option specifies that reverse lookups of IPv6 addresses should use the IP6.INT domain
and "nibble" labels as defined in RFC1886. The default is to use IP6.ARPA and binary
labels as defined in RFC2874.
N ndots This option sets the number of dots that have to be in name for it to be considered absolute.
The default value is defined using the
ndots statement in /etc/resolv.conf
,or1if
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 number
The number of UDP retries for a lookup can be changed with this option. number 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.
r Non-recursive queries can be made via this option. Setting this option clears the RD (recur-
sion desired) bit in the query which host makes. This should mean that the name server
receiving the query will not attempt to resolve name.
This 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 refer-
rals to other name servers.
T This option makes host to use a TCP connection when querying the name server. TCP
will be automatically selected for queries that require it, such as zone transfer (AXFR)
requests. By default host uses UDP when making queries.
t type This option is used to select the query type. type can be any recognised query type:
CNAME, NS, SOA, SIG, KEY, AXFR, etc. When no query type is specified, host
Section 1−−356 Hewlett-Packard Company − 1 − HP-UX 11i Version 1: September 2005