The file
/etc/host.conf
contains configuration information specific to the resolver library.
It should contain one configuration keyword per line, followed by
appropriate configuration information. The keywords recognized are
order, trim, multi, nospoof and reorder.
Each keyword is described seperately below.
order
This keyword specifies how host lookups are to be performed. It
should be followed by one or more lookup methods, seperated by commas.
Valid methods are
bind, hosts and nis.
trim
This keyword may be listed more than once. Each time it should be
followed by a single domain name, with the leading dot. When set, the
resolv+ library will automatically trim the given domain name from the
end of any hostname resolved via DNS. This is intended for use with
local hosts and domains. (Related note: trim will not affect host-
names gathered via NIS or the hosts file. Care should be taken to
insure that the first hostname for each entry in the hosts file is
fully qualified or non-qualified, as appropriate for the local
installation.)
multi
Valid values are
on and off.
If set to
on,
the resolv+ library will return all valid addresses for a host that
appears in the
/etc/hosts
file,
instead of only the first. This is
off
by default, as it may cause a substantial performance loss at sites
with large hosts files.
nospoof
Valid values are
on and off.
If set to
on,
the resolv+ library will attempt to prevent hostname spoofing to
enhance the security of
rlogin and rsh.
It works as follows: after performing a host address lookup, resolv+
will perform a hostname lookup for that address. If the two hostnames
do not match, the query will fail.
spoofalert
If this option is set to
on
and the
nospoof
option is also set, resolv+ will log a warning of the error via the
syslog facility. The default value is
off.
reorder
Valid values are
on and off.
If set to
on,
resolv+ will attempt to reorder host addresses so that local addresses
(i.e., on the same subnet) are listed first when a
gethostbyname(3)
is performed. Reordering is done for all lookup methods. The default
value is
off.