LinuxDevCenter.com
oreilly.comSafari Books Online.Conferences.





Linux in a Nutshell

This directory of Linux commands is from Linux in a Nutshell, 5th Edition.

Click on any of the 687 commands below to get a description and list of available options. All links in the command summaries point to the online version of the book on Safari Bookshelf.

Buy it now, or read it online on Safari Bookshelf.



host

host [options] name [server]

System administration command. Print information about hosts or zones in DNS. Hosts may be IP addresses or hostnames; host converts IP addresses to hostnames by default and appends the local domain to hosts without a trailing dot. Default servers are determined in /etc/resolv.conf. For more information about hosts and zones, read Chapters 1 and 2 of DNS and BIND (O'Reilly).

Options

-a

Same as -t ANY.

-c class

Search for specified resource record class (IN, CH, CHAOS, HS, HESIOD, or ANY). Default is IN.

-d

Verbose output. Same as -v.

-l

List mode. This also performs a zone transfer for the named zone. Same as -t AXFR.

-n

Perform reverse lookups for IPv6 addresses using IP6.INT domain and "nibble" labels instead of IP6.ARPA and binary labels.

-r

Do not ask contacted server to query other servers, but require only the information that it has cached.

-t type

Look for type entries in the resource record. type may be any recognized query type, such as A, AXFR, CNAME, NS, SOA, SIG, or ANY. If name is a hostname, host will look for A records by default. If name is an IPv4 or IPv6 address, it will look for PTR records.

-v

Verbose. Include all fields from resource record, even time-to-live and class, as well as "additional information" and "authoritative nameservers" (provided by the remote nameserver).

-w

Never give up on queried server.

-C

Display SOA records from all authoritative nameservers for the specified zone.

-N n

Consider names with fewer than n dots in them to be relative. Search for them in the domains listed in the search and domain directives of /etc/resolv.conf. The default is usually 1.

-R n

Retry query a maximum of n times. The default is 1.

-T

Use TCP instead of UDP to query nameserver. This is implied in queries that require TCP, such as AXFR requests.

-W n

Wait a maximum of n seconds for reply.