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Net::DNS::Packet(3)                  User Contributed Perl Documentation                 Net::DNS::Packet(3)



NAME
       Net::DNS::Packet - DNS packet object class

SYNOPSIS
       "use Net::DNS::Packet;"

DESCRIPTION
       A "Net::DNS::Packet" object represents a DNS packet.

METHODS
       new

           $packet = Net::DNS::Packet->new("example.com");
           $packet = Net::DNS::Packet->new("example.com", "MX", "IN");

           $packet = Net::DNS::Packet->new(\$data);
           $packet = Net::DNS::Packet->new(\$data, 1);  # set debugging

           ($packet, $err) = Net::DNS::Packet->new(\$data);

       If passed a domain, type, and class, "new" creates a packet object appropriate for making a DNS query
       for the requested information.  The type and class can be omitted; they default to A and IN.

       If passed a reference to a scalar containing DNS packet data, "new" creates a packet object from that
       data.  A second argument can be passed to turn on debugging output for packet parsing.

       If called in array context, returns a packet object and an error string.  The error string will only
       be defined if the packet object is undefined (i.e., couldn't be created).

       Returns undef if unable to create a packet object (e.g., if the packet data is truncated).'

       data

           $data = $packet->data;

       Returns the packet data in binary format, suitable for sending to a nameserver.

       header

           $header = $packet->header;

       Returns a "Net::DNS::Header" object representing the header section of the packet.

       question, zone

           @question = $packet->question;

       Returns a list of "Net::DNS::Question" objects representing the question section of the packet.

       In dynamic update packets, this section is known as "zone" and specifies the zone to be updated.

       answer, pre, prerequisite

           @answer = $packet->answer;

       Returns a list of "Net::DNS::RR" objects representing the answer section of the packet.

       In dynamic update packets, this section is known as "pre" or "prerequisite" and specifies the RRs or
       RRsets which must or must not preexist.

       authority, update

           @authority = $packet->authority;

       Returns a list of "Net::DNS::RR" objects representing the authority section of the packet.

       In dynamic update packets, this section is known as "update" and specifies the RRs or RRsets to be
       added or delted.

       additional

           @additional = $packet->additional;

       Returns a list of "Net::DNS::RR" objects representing the additional section of the packet.

       print

           $packet->print;

       Prints the packet data on the standard output in an ASCII format similar to that used in DNS zone
       files.

       string

           print $packet->string;

       Returns a string representation of the packet.

       answerfrom

           print "packet received from ", $packet->answerfrom, "\n";

       Returns the IP address from which we received this packet.  User-created packets will return undef
       for this method.

       answersize

           print "packet size: ", $packet->answersize, " bytes\n";

       Returns the size of the packet in bytes as it was received from a nameserver.  User-created packets
       will return undef for this method (use "length $packet->data" instead).

       push

           $packet->push(pre        => $rr);
           $packet->push(update     => $rr);
           $packet->push(additional => $rr);

           $packet->push(update => $rr1, $rr2, $rr3);
           $packet->push(update => @rr);

       Adds RRs to the specified section of the packet.

       unique_push

           $packet->unique_push(pre        => $rr);
           $packet->unique_push(update     => $rr);
           $packet->unique_push(additional => $rr);

           $packet->unique_push(update => $rr1, $rr2, $rr3);
           $packet->unique_push(update => @rr);

       Adds RRs to the specified section of the packet provided that the RRs do not already exist in the
       packet.

       safe_push

       A deprecated name for "unique_push()".

       pop

           my $rr = $packet->pop("pre");
           my $rr = $packet->pop("update");
           my $rr = $packet->pop("additional");
           my $rr = $packet->pop("question");

       Removes RRs from the specified section of the packet.

       dn_comp

           $compname = $packet->dn_comp("foo.example.com", $offset);

       Returns a domain name compressed for a particular packet object, to be stored beginning at the given
       offset within the packet data.  The name will be added to a running list of compressed domain names
       for future use.

       dn_expand

           use Net::DNS::Packet qw(dn_expand);
           ($name, $nextoffset) = dn_expand(\$data, $offset);

           ($name, $nextoffset) = Net::DNS::Packet::dn_expand(\$data, $offset);

       Expands the domain name stored at a particular location in a DNS packet.  The first argument is a
       reference to a scalar containing the packet data.  The second argument is the offset within the
       packet where the (possibly compressed) domain name is stored.

       Returns the domain name and the offset of the next location in the packet.

       Returns (undef, undef) if the domain name couldn't be expanded.

       sign_tsig

           $key_name = "tsig-key";
           $key      = "awwLOtRfpGE+rRKF2+DEiw==";

           $update = Net::DNS::Update->new("example.com");
           $update->push("update", rr_add("foo.example.com A 10.1.2.3"));

           $update->sign_tsig($key_name, $key);

           $response = $res->send($update);

       Signs a packet with a TSIG resource record (see RFC 2845).  Uses the following defaults:

           algorithm   = HMAC-MD5.SIG-ALG.REG.INT
           time_signed = current time
           fudge       = 300 seconds

       If you wish to customize the TSIG record, you'll have to create it yourself and call the appropriate
       Net::DNS::RR::TSIG methods.  The following example creates a TSIG record and sets the fudge to 60
       seconds:

           $key_name = "tsig-key";
           $key      = "awwLOtRfpGE+rRKF2+DEiw==";

           $tsig = Net::DNS::RR->new("$key_name TSIG $key");
           $tsig->fudge(60);

           $query = Net::DNS::Packet->new("www.example.com");
           $query->sign_tsig($tsig);

           $response = $res->send($query);

       You shouldn't modify a packet after signing it; otherwise authentication will probably fail.

       sign_sig0

       SIG0 support is provided through the Net::DNS::RR::SIG class. This class is not part of the default
       Net::DNS distribution but resides in the Net::DNS::SEC distribution.

           $update = Net::DNS::Update->new("example.com");
           $update->push("update", rr_add("foo.example.com A 10.1.2.3"));
           $update->sign_sig0("Kexample.com+003+25317.private");

       SIG0 support is experimental see Net::DNS::RR::SIG for details.

       The method will call "Carp::croak()" if Net::DNS::RR::SIG cannot be found.

COPYRIGHT
       Copyright (c) 1997-2002 Michael Fuhr.

       Portions Copyright (c) 2002-2004 Chris Reinhardt.

       Portions Copyright (c) 2002-2005 Olaf Kolkman

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

SEE ALSO
       perl(1), Net::DNS, Net::DNS::Resolver, Net::DNS::Update, Net::DNS::Header, Net::DNS::Question,
       Net::DNS::RR, RFC 1035 Section 4.1, RFC 2136 Section 2, RFC 2845



perl v5.8.8                                      2007-06-21                              Net::DNS::Packet(3)