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Net-DNS-Nameserver-Trivial-0.305
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/ Net::DNS::Nameserver::Trivial

NAME

Net::DNS::Nameserver::Trivial - Trivial DNS server, that is based on Net::DNS::Nameserver module.

SYNOPSIS

        use Net::DNS::Nameserver::Trivial;
        
        # Configuration of zone(s) -----------------------------------------
        
        my $zones = {
                 '_'     => {
                                  'slaves'      => '10.1.0.1'
                                 },
                                 
                 'A'     => {
                                  'ns.example.com'   => '10.11.12.13',
                                  'mail.example.com' => '10.11.12.14',
                                  'web.example.com'  => '10.11.12.15',
                                  'srv.example.com'  => '10.11.12.16'
                                 },
                                
                 'AAAA'  => {
                                   'v6.example.com'      =>     'fe80::20c:29ff:fee2:ed62', 
                                 },
                                 
                 'CNAME' => {
                                          'srv.example.com' => 'dns.example.com'
                                 },
                                 
                 'MX'    => {
                                   'example.com' => 'mail.example.com'
                                 },
                                 
                 'NS'    => {
                                        'example.com' => 'ns.example.com'
                                 },
                                 
                 'SOA'   => {
                                        'example.com' => 'ns.example.com'
                                 }
           };

        # Configuration of server ------------------------------------------
        my $params = {
        
                'FLAGS'         => {
                                        'ra' => 0,      # recursion available
                                 },

                'RESOLVER'      => {
                                        'tcp_timeout'   => 50,
                                        'udp_timeout'   => 50
                                 },
                                 
                'CACHE'         => {
                                        'size'                  => 32m, # size of cache
                                        'expire'        => 3d,  # expire time of cache
                                        'init'                  => 1,   # clear cache at startup
                                        'unlink'                => 1,   # destroy cache on exit
                                        'file'          => '../var/lib/cache.db'        # cache
                                 },
                                 
                'SERVER'        => {
                                        'address'               => '0.0.0.0', # all interfaces
                                        'port'                  => 53,
                                        'verbose'               => 0,
                                        'truncate'      => 1,   # truncate too big 
                                        'timeout'               => 5    # seconds
                                 },

                'LOG'           => {
                                        'file'                  => '/var/log/dns/mainlog.log',
                                        'level'                 => 'INFO'
                                 },
                                 
        };

        # Run server -------------------------------------------------------
        
        my $ns = Net::DNS::Nameserver::Trivial->new( $zones, $params );
    $ns->main_loop;
        
        #
        # ...OR SHORT VERSION with configuration files
        #

        use Config::Tiny;
        use Net::DNS::Nameserver::Trivial;
        
        # Read in config of zone -------------------------------------------
        my $zones       = Config::Tiny->read( '../etc/dom.ini' );
        
        # Read in config of server -----------------------------------------
        my $params      = Config::Tiny->read( '../etc/dns.ini' );

        # Run server -------------------------------------------------------
        my $ns = Net::DNS::Nameserver::Trivial->new( $zones, $params );
        $ns->main_loop;

DESCRIPTION

The Net::DNS::Nameserver::Trivial is a very simple nameserver, that is sufficient for local domains. It supports cacheing, slaves, zone transfer and common records such as A, AAAA, SOA, NS, MX, TXT, PTR, CNAME. This module was tested in an environment with over 1000 users and for now is running in a production environment.

The main goal was to produce server, that is very easy in configuration and it can be setup in a few seconds. So You should consider BIND if for some reasons You need more powerful and complex nameserver.

This module was prepared to cooperete with Config::Tiny, so it is possible to prepare configuration files and run server with them, as it was shown in an example above.

WARNING

This version is incompatible with previous versions, because of new format of second configuration file. However modifications are simple.

SUBROUTINES/METHODS

new( $zones, $params )

This is constructor. You have to pass to it hash with configuration of zones and second hash - with configuration for server.

The first hash sould contains sections (as shown in a SINOPSIS):

_

This section is a hash, that should contains information of slaves of our server. For example:

        '_' => {
                'slaves'      => '10.1.0.1'
        }
A

This section is a hash, that is a mapping FDQN to IPv4, for example:

        'A' => {
                  'ns.example.com'   => '10.11.12.13',
                  'mail.example.com' => '10.11.12.14',
                  'web.example.com'  => '10.11.12.15',
                  'srv.example.com'  => '10.11.12.16'
                 }
AAAA

This section is a hash, that is a mapping FDQN to IPv6, for example:

        'AAAA' => {
                'v6.example.com'  => 'fe80::20c:29ff:fee2:ed62', 
        }
MX

This section is a hash, that contains information about mail servers for domains. For example, if mail.example.com is a mail server for domain example.com, a configuration should looks like this:

        'MX' => {
                'example.com' => 'mail.example.com'
        }
CNAME

This section is a hash, that contains aliases for hosts. For example, if alias.example.com and alias1.example.com are aliases for a server srv.example.com, a configuration should looks like this:

        'CNAME' => {
                'srv.example.com' => 'alias.example.com, alias1.example.com'
        }
NS

This section is a hash, that contains information about nameservers for a domain. For example:

        'NS' => {
                'example.com' => 'ns.example.com'
        }
SOA

This section is a hash, that contains information about authoritative nameserver for a domain. For example:

        'SOA' => {
                'example.com' => 'ns.example.com'
        }

The second hash should contains variables sufficient for configuration of server, cache, logs, etc. The meaning of hash elements was shown below.

SERVER

This section describes options of server.

timeout

Timeout for idle connections.

address

Local IP address to listen on. Server will be listenting on all interfecas if You specify 0.0.0.0.

port

Local port to listen on.

truncate

Truncates UDP packets that are to big for the reply

verbose

Be verbose. It is useful only for debugging.

CACHE

This section describes options of server's cache.

size

A size of cache, that will be used by server.

expire

Expiration time of entries in a cache. It can be diffrent than TTL value. It is effective if makeing of connection to other server is too expensive (i.e. too long).

init

Clear cache at startup.

file

A path to cache file.

Unlink a cache file on exit.

LOG

This section describes options of server's log.

file

A path to log file.

level

Log level.

RESLOVER

This section describes options of resolver.

tcp_timeout

A timeout for TCP connections.

udp_timeout

A timeout for UDP connections.

main_loop()

This method starts main loop of a nameserver. See an example in a SINOPSIS.

USING CONFIGURATION FILES - examples

Net::DNS::Nameserver::Trivial was prepared to cooperate with Config::Tiny module. It is possible to prepare configuration files for zones and for server and then make server server run using those files.

Config file for zone example.com could looks like this:

        slaves              = 10.1.0.1

        [NS]
        example.com         = ns.example.com

        [SOA]
        example.com         = ns.example.com

        [MX]
        example.com         = mail.example.com'

        [AAAA]

        [CNAME]
        srv.example.com     = alias.example.com, alias1.example.com

        [A]
        ns.example.com      = 10.11.12.13
        mail.example.com    = 10.11.12.14
        web.example.com     = 10.11.12.15
        srv.example.com     = 10.11.12.16

Config file for server could looks like this:

        [FLAGS]
        ra                              = 0

        [RESOLVER]
        tcp_timeout             = 50
        udp_timeout             = 50

        [CACHE]
        size                    = 32m
        expire                  = 3d
        init                    = 1
        unlink                  = 1
        file                    = /var/lib/cache.db

        [SERVER]
        address                 = 0.0.0.0
        port                    = 53
        verbose                 = 0
        truncate        = 1
        timeout                 = 5

        [LOG]
        file                    = /var/log/dns/mainlog.log
        level                   = INFO

And then a code of server shold looks like this:

        use Config::Tiny;
        use Net::DNS::Nameserver::Trivial;
        
        # Read in config of zone -------------------------------------------
        my $zones       = Config::Tiny->read( '/path/to/zone/file.ini' );
        
        # Read in config of server -----------------------------------------
        my $params      = Config::Tiny->read( '/path/to/server/config.ini' );

        # Run server -------------------------------------------------------
        my $ns = Net::DNS::Nameserver::Trivial->new( $zones, $params );
        $ns->main_loop;

A complete example is placed in the example directory.

DEPENDENCIES

Net::IP::XS
Net::DNS
Log::Tiny
List::MoreUtils
Cache::FastMmap
Regexp::IPv6

INCOMPATIBILITIES

None known.

BUGS AND LIMITATIONS

I'm sure, that they must be there :-) ...but if You found one, give me a feedback.

AUTHOR

Strzelecki Łukasz <l.strzelecki@ita.wat.edu.pl>

LICENCE AND COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html