MAN page from Old RedHat 6.X bind-utils-9.1.1-1.i386.rpm

HOST

Section: User Commands (1)
Index
BSD mandoc
BIND9 9

NAME

host - DNS lookup utility

SYNOPSIS

host[-aCdlnrTwv][-c class][-N ndots][-R number][-t type][-W wait]name[server]

DESCRIPTION

hostis 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,hostprints a short summary of its command line arguments and options.

nameis the domain name that is to be looked up.It can also be a dotted-decimal IPv4 addressor a colon-delimited IPv6 address,in which casehostwill by default perform a reverse lookup for that address.serveris an optional argument which is either the name or IP address of thename server thathostshould query instead of the server or servers listed in/etc/resolv.conf

The-a(all) option is equivalent to setting the-voption and askinghostto make a query of type ANY.

When the-Coption is used,hostwill attempt to display the SOA records for zonenamefrom all the listed authoritative name servers for that zone.The list of name servers is defined by the NS records that are found forthe zone.

The-coption instructs to make a DNS query of classclass This can be used to lookup Hesiod or Chaosnet class resource records.The default class is IN: Internet.

Verbose output is generated byhostwhen the-dor-voption is used.The two options are equivalent.They have been provided for backwards compatibility.In previous versions, the-doption switched on debugging traces and-venabled verbose output.

List mode is selected by the-loption.This makeshostperform a zone transfer for zonename The argument is provided for compatibility with older implemementations.This option is equivalent to making a query of type AXFR.

The-noption specifies that reverse lookups of IPv6 addresses shoulduse 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.

The-Noption sets the number of dots that have to be innamefor it to be considered absolute. The default value is thatdefined using the ndots statement in/etc/resolv.conf or 1 if no ndots statement is present. Names with fewerdots are interpreted as relative names and will be searched for in the domains listed in the searchordomaindirective in/etc/resolv.conf

The number of UDP retries for a lookup can be changed with the-Roption.numberindicates how many timeshostwill repeat a query that does not get answered.The default number of retries is 1.Ifnumberis negative or zero, the number of retries will default to 1.

Non-recursive queries can be made via the-roption.Setting this option clears theRD- recursion desired - bit in the query whichhostmakes.This should mean that the name server receiving the query will not attemptto resolvename The-roption enableshostto mimic the behaviour of a name server by making non-recursive queriesand expecting to receive answers to those queries that are usuallyreferrals to other name servers.

By defaulthostuses UDP when making queries.The-Toption makes it 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.

The-toption is used to select the query type.typecan be any recognised query type: CNAME, NS, SOA, SIG, KEY, AXFR, etc.When no query type is specified,hostautomatically selects an appropriate query type.By default it looks for A records, but if the-Coption was given, queries will be made for SOA records,and ifnameis a dotted-decimal IPv4 address or colon-delimited IPv6 address,hostwill query for PTR records.

The time to wait for a reply can be controlled through the-Wand-woptions.The-Woption makeshostwait forwaitseconds.Ifwaitis less than one,the wait interval is set to one second.When the-woption is used,hostwill effectively wait forever for a reply.The time to wait for a response will be set to the number of secondsgiven by the hardware's maximum value for an integer quantity.

FILES

/etc/resolv.conf

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