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
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