NAME
resolver - resolver configuration file
SYNOPSIS
/etc/resolv.conf
DESCRIPTION
The resolver is a set of routines in the C library
(resolv(3)) that provide access to the Internet Domain Name
System. The resolver configuration file contains informa-
tion 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 will be on
the local machine, the domain name is determined from the
host name, and the domain search path is constructed from
the domain name.
The different configuration options are:
nameserver
Internet address (in dot notation) of a name server
that the resolver should query. Up to MAXNS (currently
3) name servers may 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 to
try a name server, and if the query times out, try the
next, until out of name servers, then repeat trying all
the name servers until a maximum number of retries are
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(2); the domain part is taken to be every-
thing 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 com-
ponents in their names. This may 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 will generate a
lot of network traffic if the servers for the listed
domains are not local, and that queries will 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 domain and search keywords are mutually exclusive. If
more than one instance of these keywords is present, the
last instance will override.
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.
FILES
/etc/resolv.conf
SEE ALSO
gethostbyname(3N), resolver(3), hostname(7), named(8)
Name Server Operations Guide for BIND