Commands Reference, Volume 2

host Command

Purpose

Resolves a host name into an Internet address or an Internet address into a host name.

Syntax

host [ -a ] [ -c Class ] [ -d ] [ -n ] [ -r ] [ -t Type ] [ -v ] [ -w ] [ -z ] [ Hostname | Address ] [ Server ]

The /usr/bin/host command returns the Internet address of a host machine when the HostName parameter is specified and the name of the host when the Address parameter is specified. The host command also displays any aliases associated with the HostName parameter.

If the local host is using the DOMAIN protocol, the local or remote name server database is queried before searching the local /etc/hosts file.

The host command may also return other name records found in the DNS (Domain Name System). The -z flag specifies this mode. The other flags allow for the customization of the query.

Flags

-a	Equivalent to using "-v -t *"
-c Class	Specifies the class to look in when searching non-Internet data. Valid classes are: IN Internet class CHAOS Chaos class HESIOD MIT Althena Hesiod class ANY Wildcard (any of the above) * Wildcard (any of the above)
-d	Turns on debugging mode.
-n	Equivalent to issuing the /usr/bin/hostnew command.
-r	Disables recursive processing.
-t Type	Specifies the type of record to query for. Valid types are: A Host's Internet address CNAME Canonical name for an alias HINFO Host CPU and operating system type KEY Security Key Record MINFO Mailbox or mail list information MX Mail exchanger NS Nameserver for the named zone PTR Host name if the query is an Internet address; otherwise, the pointer to other information SIG Signature Record SOA Domain's "start-of-authority" information TXT Text information UINFO User information WKS Supported well-known services
-v	Verbose mode.
-w	Waits forever for a reply from the DNS server.
-z	Uses the new output that displays resource record information.

Parameters

Address	Specifies the Internet address of the host machine to use in resolving the host name. The Address parameter must be a valid Internet address in dotted decimal format.
HostName	Specifies the name of the host machine to use in resolving the Internet address. The HostName parameter can be either a unique host name or a well-known host name (such as nameserver, printserver, or timeserver, if these exist).
Server	Specifies the nameserver to query.

Examples

To display the address of a host machine named mephisto, enter:
```
host mephisto
```
Information similar to the following is displayed:
```
mephisto is 192.100.13.5, Aliases: engr, sarah
```
To display the host whose address is 192.100.13.1, enter:
```
host 192.100.13.1
```
Information similar to the following is displayed:
```
mercutio is 192.100.13.1
```

Files

/etc/hosts

Contains the Internet Protocol (IP) name and addresses of hosts on the local network.

Related Information

The hostname command.

The named daemon.

Network Overview in AIX 5L Version 5.1 System Management Guide: Communications and Networks.