HP-UX Reference (11i v3 07/02) - 4 File Formats (vol 8)

r
resolver(4) resolver(4)
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 net-
work numbers specified in the address list. This option allows you to specify which
subnets and networks for
gethostbyname()
to prefer if it receives multiple
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 environ-
ment 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
1535.
372 Hewlett-Packard Company − 2 − HP-UX 11i Version 3: February 2007