# phpman > perldoc > Net::DNS::DomainName

## NAME
    [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown) - DNS name representation

## SYNOPSIS
        use [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown);

        $object = [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown)->new('example.com');
        $name = $object->name;
        $data = $object->encode;

        ( $object, $next ) = [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown)->decode( \$data, $offset );

## DESCRIPTION
    The [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown) module implements the concrete representation of DNS domain names used
    within DNS packets.

    [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown) defines methods for encoding and decoding wire format octet strings. All
    other behaviour is inherited from [Net::DNS::Domain](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomain/markdown).

    The [Net::DNS::DomainName1035](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName1035/markdown) and [Net::DNS::DomainName2535](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName2535/markdown) packages implement disjoint domain
    name subtypes which provide the name compression and canonicalisation specified by RFC1035 and
    RFC2535. These are necessary to meet the backward compatibility requirements introduced by
    RFC3597.

## METHODS
  new
        $object = [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown)->new('example.com');

    Creates a domain name object which identifies the domain specified by the character string
    argument.

  canonical
        $data = $object->canonical;

    Returns the canonical wire-format representation of the domain name as defined in RFC2535(8.1).

  decode
        $object = [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown)->decode( \$buffer, $offset, $hash );

        ( $object, $next ) = [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown)->decode( \$buffer, $offset, $hash );

    Creates a domain name object which represents the DNS domain name identified by the wire-format
    data at the indicated offset within the data buffer.

    The argument list consists of a reference to a scalar containing the wire-format data and
    specified offset. The optional reference to a hash table provides improved efficiency of
    decoding compressed names by exploiting already cached compression pointers.

    The returned offset value indicates the start of the next item in the data buffer.

  encode
        $data = $object->encode;

    Returns the wire-format representation of the domain name suitable for inclusion in a DNS packet
    buffer.

## [Net::DNS::DomainName1035](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName1035/markdown)
    [Net::DNS::DomainName1035](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName1035/markdown) implements a subclass of domain name objects which are to be encoded
    using the compressed wire format defined in RFC1035.

        use [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown);

        $object = [Net::DNS::DomainName1035](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName1035/markdown)->new('compressible.example.com');
        $data   = $object->encode( $offset, $hash );

        ( $object, $next ) = [Net::DNS::DomainName1035](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName1035/markdown)->decode( \$data, $offset );

    Note that RFC3597 implies that the RR types defined in RFC1035 section 3.3 are the only types
    eligible for compression.

  encode
        $data = $object->encode( $offset, $hash );

    Returns the wire-format representation of the domain name suitable for inclusion in a DNS packet
    buffer.

    The optional arguments are the offset within the packet data where the domain name is to be
    stored and a reference to a hash table used to index compressed names within the packet.

    If the hash reference is undefined, encode() returns the lowercase uncompressed canonical
    representation defined in RFC2535(8.1).

## [Net::DNS::DomainName2535](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName2535/markdown)
    [Net::DNS::DomainName2535](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName2535/markdown) implements a subclass of domain name objects which are to be encoded
    using uncompressed wire format.

    Note that RFC3597, and latterly RFC4034, specifies that the lower case canonical encoding
    defined in RFC2535 is to be used for RR types defined prior to RFC3597.

        use [Net::DNS::DomainName](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName/markdown);

        $object = [Net::DNS::DomainName2535](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName2535/markdown)->new('incompressible.example.com');
        $data   = $object->encode( $offset, $hash );

        ( $object, $next ) = [Net::DNS::DomainName2535](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomainName2535/markdown)->decode( \$data, $offset );

  encode
        $data = $object->encode( $offset, $hash );

    Returns the uncompressed wire-format representation of the domain name suitable for inclusion in
    a DNS packet buffer.

    If the hash reference is undefined, encode() returns the lowercase canonical form defined in
    RFC2535(8.1).

## COPYRIGHT
    Copyright (c)2009-2011 Dick Franks.

    All rights reserved.

## LICENSE
    Permission to use, copy, modify, and distribute this software and its documentation for any
    purpose and without fee is hereby granted, provided that the original copyright notices appear
    in all copies and that both copyright notice and this permission notice appear in supporting
    documentation, and that the name of the author not be used in advertising or publicity
    pertaining to distribution of the software without specific prior written permission.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
    BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
    DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

## SEE ALSO
    perl, [Net::DNS](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS/markdown), [Net::DNS::Domain](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ADomain/markdown), RFC1035, RFC2535, RFC3597, RFC4034