# phpman > perldoc > Net::DNS::RR::SVCB

## NAME
    [Net::DNS::RR::SVCB](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ARR%3A%3ASVCB/markdown) - DNS SVCB resource record

## SYNOPSIS
        use [Net::DNS](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS/markdown);
        $rr = [Net::DNS::RR](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ARR/markdown)->new('name HTTPS SvcPriority TargetName SvcParams');

## DESCRIPTION
    DNS Service Binding (SVCB) resource record

    Service binding and parameter specification via the DNS (SVCB and HTTPS RRs)

## METHODS
    The available methods are those inherited from the base class augmented by the type-specific
    methods defined in this package.

    Use of undocumented package features or direct access to internal data structures is discouraged
    and could result in program termination or other unpredictable behaviour.

### SvcPriority
        $svcpriority = $rr->svcpriority;
        $rr->svcpriority( $svcpriority );

    The priority of this record (relative to others, with lower values preferred). A value of 0
    indicates AliasMode.

### TargetName
        $rr->targetname( $targetname );
        $effecivetarget = $rr->targetname;

    The domain name of either the alias target (for AliasMode) or the alternative endpoint (for
    ServiceMode).

    For AliasMode SVCB RRs, a TargetName of "." indicates that the service is not available or does
    not exist.

    For ServiceMode SVCB RRs, a TargetName of "." indicates that the owner name of this record must
    be used as the effective TargetName.

  mandatory, alpn, no-default-alpn, port, ipv4hint, ech, ipv6hint
        $rr = [Net::DNS::RR](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ARR/markdown)->new( 'svcb.example. SVCB 1 svcb.example. port=1234' );

        $rr->[port(1234)](https://www.chedong.com/phpMan.php/man/port/1234/markdown);
        $string = $rr->port();      # \004\210
        $rr->key3($string);

    Constructor methods for mnemonic SvcParams defined in draft-ietf-dnsop-svcb-https. When invoked
    without arguments, the methods return the presentation format value for the underlying key. The
    behaviour with undefined arguments is not specified.

  keyNN
        $keynn = $rr->keyNN;
        $rr->keyNN( $keynn );
        $rr->keyNN( undef );

    Generic constructor and accessor methods for SvcParams. The key index NN is a decimal integer in
    the range 0 .. 65535. The method argument and returned value are both presentation format
    strings. The method returns the undefined value if the key is not present. The specified key
    will be deleted if the value is undefined.

## COPYRIGHT
    Copyright (c)2020-2021 Dick Franks.

    All rights reserved.

    Package template (c)2009,2012 O.M.Kolkman and R.W.Franks.

## 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::RR](https://www.chedong.com/phpMan.php/perldoc/Net%3A%3ADNS%3A%3ARR/markdown), draft-ietf-dnsop-svcb-https