Mac OS X in a Nutshell

Name

host

Synopsis

host [options] host [server]
host [options] domain [server]

Prints information about specified 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, try Chapters 1 and 2 of DNS and BIND (O’Reilly & Associates, Inc., 2001).

Options

-a

all, same as -t ANY.

-c class

Search for specified resource record class (in[ternet], cs[net], ch[aos], hs/hesiod, or any). Default is in. The chaos and csnet classes, although defined in RFC1035, are rejected as invalid classes by the host command.

-d

Debugging mode. -dd is a more verbose version.

-l domain

List all machines in domain.

-r

No recursion. Do not ask contacted server to query other servers, but require only the information that it has cached.

-s

Chase signatures back to parent key (DNSSEC).

-t type

Look for type entries in the resource record. Acceptable values for type are: a, ns, md, mf, cnames, soa, mb, mg, mr, null, wks, ptr, hinfo, minfo, mx, any, and * (careful, the shell loves those asterisks; be sure to escape them).

-v

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

-w

Wait forever for a response from a queried server.