NAME

resolver − resolver configuration file

SYNOPSIS

/etc/resolv.conf

DESCRIPTION

The resolver is a set of routines in the C library (see resolver(3N)) that provide access to the Internet Domain Name System. The resolver configuration file contains information that is read by the resolver routines the first time they are invoked by a process. The file is designed to be human-readable, and contains a list of keywords with values that provide various types of resolver information.

On a normally configured system this file should not be necessary.  The only name server to be queried is on the local machine, the domain name is determined from the host name, and the domain search path is constructed from the domain name. 

Recognized configuration options include:

nameserver Internet address (in dot notation) of a name server that the resolver should query.  Up to MAXNS (currently 3) name servers can be listed, one per keyword.  If there are multiple servers, the resolver library queries them in the order listed.  If no nameserver entries are present, the default is to use the name server on the local machine.  (The algorithm used is:  Try a name server; if the query times out, try the next and continue until all name servers have been tried, then repeat trying all the name servers until a maximum number of retries have been made made). 

domain Local domain name.  Most queries for names within this domain can use short names relative to the local domain.  If no domain entry is present, the domain is determined from the local host name returned by gethostname() (see gethostname(2)); the domain part is interpreted as everything after the first ..  Finally, if the host name does not contain a domain part, the root domain is assumed. 

search Search list for host-name lookup.  The search list is normally determined from the local domain name; by default, it begins with the local domain name, then successive parent domains that have at least two components in their names.  This can be changed by listing the desired domain search path following the search keyword with spaces or tabs separating the names.  Most resolver queries will be attempted using each component of the search path in turn until a match is found.  Note that this process may be slow and generates a lot of network traffic if the servers for the listed 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)

The domain and search keywords are mutually exclusive.  If more than one instance of these keywords is present, the last instance overrides. 

The keyword and value must appear on a single line, and the keyword (e.g.  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 res_init(3N)).

EXAMPLES

A typical resolv.conf file resembles the following:

domain div.inc.com
nameserver 15.19.8.119
nameserver 15.19.8.197

AUTHOR

resolver was developed by the University of California, Berkeley. 

FILES

/etc/resolv.conf resolver configuration file

SEE ALSO

named(1m), resolver(3N), gethostent(3N), hostname(5)

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992