Name

host [options] name [server] — bind-utils

Synopsis

/usr/bin stdin stdout - file -- opt --help --version

The host command looks up the hostname or IP address of a remote machine by querying DNS.

$ host www.redhat.com
www.redhat.com has address 66.187.232.50
$ host 66.187.232.50
50.232.187.66.in-addr.arpa domain name pointer www.redhat.
com.

It can also find out much more:

$ host -a www.redhat.com
Trying "www.redhat.com"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50419
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3,
ADDITIONAL: 3

;; QUESTION SECTION:
;www.redhat.com.      IN  ANY

;; ANSWER SECTION:
www.redhat.com.    196  IN  A  66.187.232.50

;; AUTHORITY SECTION:
redhat.com.    90535  IN  NS  ns2.redhat.com.
redhat.com.    90535  IN  NS  ns3.redhat.com.
redhat.com.    90535  IN  NS  ns1.redhat.com.

;; ADDITIONAL SECTION:
ns2.redhat.com.    143358  IN  A  66.187.224.210
ns3.redhat.com.    143358  IN  A  66.187.229.10
ns1.redhat.com.    143358  IN  A  66.187.233.210

but a full discussion of nameservers is beyond the scope of this book. The final, optional “server” parameter lets you specify a particular nameserver for the query. Here’s one at comcast.net:

$ host www.redhat.com ns01.jdc01.pa.comcast.net
Using domain server:
Name: ns01.jdc01.pa.comcast.net
Address: 66.45.25.71#53
Aliases:
www.redhat.com has address 66.187.232.50

To see all options, type host by itself.

Useful options

-a

Display all available information.

-t

Choose the type of nameserver query: A, AXFR, CNAME, HINFO, KEY, MX, NS, PTR, SIG, SOA, and so on.

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