- 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.
- d v
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 versions, 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,
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 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
(recursion 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
referrals 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
automatically selects an appropriate query type.
By default it looks for A records, but if the
C
option was given, queries will be made for SOA records;
and if
name
is a dotted-decimal IPv4 address or colon-delimited IPv6 address,
host
will query for PTR records.
- W wait
The time to wait for a reply can be controlled through the
W
option.
This option makes
host
wait for
wait
seconds.
If
wait
is less than 1,
the wait interval is set to one second.
- w
When this
option is used,
host
will effectively 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.
