HP-UX Reference (11i v2 04/09) - 4 File Formats (vol 8)

r
resolver(4) resolver(4)
domains are not local, and that queries time out if no server is available for one of
the domains.
The search list is currently limited to six domains with a total of 256 characters.
The first domain in the search list must be the local domain for short names to work
properly in various files (such as
.rhosts and inetd.sec)
sortlist Causes addresses returned by gethostbyname(3N) to be sorted in accordance with
network numbers specified in the address list. This option allows you to specify
which subnets and networks for
gethostbyname()
to prefer if it receives multi-
ple addresses as the result of a query from the domain nameserver. The syntax is
sortlist addresslist
A sortlist is specified by IP address netmask pairs. The netmask is optional and
defaults to the netmask of the net. The IP address and optional netmask pairs are
separated by slashes. Up to 10 pairs may be specified. The pairs are separated by
blank spaces.
The following sortlist directive sorts the address on 128.32.42 subnet,
sortlist 128.32.42.0/255.255.255.0
The argument after the slash is the subnet mask for the subnet in question. To
prefer an entire network, you can omit the slash and the subnet mask:
sortlist 128.32.0.0
gethostbyname() sorts any addresses in a reply that match these arguments
into the order in which they appear in the sortlist, and appends those addresses
that do not match to the end.
options Options allows certain internal resolver variables to be modified. The syntax is
options option ...
where currently the option supported is the following:
ndots:n Set a threshold for the number of dots which must appear in a
name given to res_query (see resolver (3N)) before an initial
absolute query will be made. The default for n is ‘‘1’’, meaning that
if there are any dots in a name, the name will be tried first as an
absolute name before any search list elements are appended to it.
The
domain and search keywords are mutually exclusive. If more than one instance of these key-
words is present, the last instance overrides.
The
search keyword of a system’s resolv.conf file can be overridden on a per-process basis by set-
ting the environment variable LOCALDOMAIN to a space-separated list of search domains. The
options keyword of a system’s resolv.conf file can be amended on a per-process basis by setting
the environment variable RES_OPTIONS to a space separated list of resolver options as explained above
under options.
The keyword and value must appear on a single line, and the keyword (for example
nameserver) must
start the line. The value follows the keyword, separated by white space.
Note that the resolver routine
res_init() silently ignores errors when reading this file (see
resolver (3N)).
EXAMPLES
A typical
resolv.conf file resembles the following:
domain div.inc.com
nameserver 15.19.8.119
nameserver 15.19.8.197
WARNINGS
In order to reduce situations that may cause connections to unintended destinations, the administrator
should carefully select which domains are put in the search list in the resolv.conf file. HP recom-
mends that the possible domains for the search list be limited to those domains administered within your
trusted organization. For more information on the security implications of search lists please see RFC
Section 4−−276 Hewlett-Packard Company − 2 − HP-UX 11i Version 2: September 2004