NAME

rhosts − host name data base

DESCRIPTION

The rhosts file contains information regarding the known hosts on the network.  For each host a single line should be present with the following information. 

Internet address
official host name
aliases

Internet addresses are specified in the conventional “.” notation using the inet_addr() routine from the Internet address manipulation library, inet(3N). Host names may contain any printable character other than a space, tab, newline, or comment character.

Items are separated by any number of blanks and/or tab characters.  Characters between a “#” and the end of the line are comments and are not interpreted by routines which search the file.  For hosts residing on the ARPANET, this file is normally created from the official host data base maintained at the Network Information Control Center (NIC), although local changes may be required to bring it up to date regarding unofficial aliases and/or unknown hosts.  As the database maintained at NIC is incomplete, use of the name server is recommended for sites on the DARPA Internet. 

When the name server named(8) is in use, this file provides a backup when the name server is not running. For the name server, it is suggested that only a few addresses be included in this file. These include addresses for the local interfaces that ifconfig(8C) needs at boot time and a few machines on the local network.

EXAMPLES

A properly functioning network is extremely sensitive to the contents of /etc/hosts.  Below are examples of the minimum requirements for /etc/hosts on a network with only two hosts, fred and ethyl. 

The same host file may be used on both machines:

127.0.0.1  loop  localhost

address1  fred
address2  ethyl

The two addresses, address1 and address2 must refer to the same network, as described in inet(3N). The network must also appear in /etc/networks, as described in networks(5).

FILES

/etc/hosts

SEE ALSO

gethostent(3N), inet(3N), networks(5), ifconfig(8c), named(8)

September 29, 2021