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

NAME
       Net::DNS::Header - DNS packet header class

SYNOPSIS
       "use Net::DNS::Header;"

DESCRIPTION
       A "Net::DNS::Header" object represents the header portion of a DNS
       packet.

MMEETTHHOODDSS
       nneeww

           $header = Net::DNS::Header->new;
           $header = Net::DNS::Header->new(\$data);

       Without an argument, "new" creates a header object appropriate for
       making a DNS query.

       If "new" is passed a reference to a scalar containing DNS packet data,
       it creates a header object from that data.

       Returns uunnddeeff if unable to create a header object (e.g., if the data is
       incomplete).

       pprriinntt

           $header->print;

       Dumps the header data to the standard output.

       ssttrriinngg

           print $header->string;

       Returns a string representation of the header object.

       iidd

           print "query id = ", $header->id, "\n";
           $header->id(1234);

       Gets or sets the query identification number.

       qqrr

           print "query response flag = ", $header->qr, "\n";
           $header->qr(0);

       Gets or sets the query response flag.

       ooppccooddee

           print "query opcode = ", $header->opcode, "\n";
           $header->opcode("UPDATE");

       Gets or sets the query opcode (the purpose of the query).

       aaaa

           print "answer is ", $header->aa ? "" : "non-", "authoritative\n";
           $header->aa(0);

       Gets or sets the authoritative answer flag.

       ttcc

           print "packet is ", $header->tc ? "" : "not ", "truncated\n";
           $header->tc(0);

       Gets or sets the truncated packet flag.

       rrdd

           print "recursion was ", $header->rd ? "" : "not ", "desired\n";
           $header->rd(0);

       Gets or sets the recursion desired flag.

       ccdd

           print "checking was ", $header->cd ? "not" : "", "desired\n";
           $header->cd(0);

       Gets or sets the checking disabled flag.

       rraa

           print "recursion is ", $header->ra ? "" : "not ", "available\n";
           $header->ra(0);

       Gets or sets the recursion available flag.

       aadd

           print "The result has ", $header->ad ? "" : "not", "been verified\n"

       Relevant in DNSSEC context.

       (The AD bit is only set on answers where signatures have been
       cryptographically verified or the server is authoritative for the data
       and is allowed to set the bit by policy.)

       rrccooddee

           print "query response code = ", $header->rcode, "\n";
           $header->rcode("SERVFAIL");

       Gets or sets the query response code (the status of the query).

       qqddccoouunntt,, zzooccoouunntt

           print "# of question records: ", $header->qdcount, "\n";
           $header->qdcount(2);

       Gets or sets the number of records in the question section of the
       packet.  In dynamic update packets, this field is known as "zocount"
       and refers to the number of RRs in the zone section.

       aannccoouunntt,, pprrccoouunntt

           print "# of answer records: ", $header->ancount, "\n";
           $header->ancount(5);

       Gets or sets the number of records in the answer section of the packet.
       In dynamic update packets, this field is known as "prcount" and refers
       to the number of RRs in the prerequisite section.

       nnssccoouunntt,, uuppccoouunntt

           print "# of authority records: ", $header->nscount, "\n";
           $header->nscount(2);

       Gets or sets the number of records in the authority section of the
       packet.  In dynamic update packets, this field is known as "upcount"
       and refers to the number of RRs in the update section.

       aarrccoouunntt,, aaddccoouunntt

           print "# of additional records: ", $header->arcount, "\n";
           $header->arcount(3);

       Gets or sets the number of records in the additional section of the
       packet.  In dynamic update packets, this field is known as "adcount".

       ddaattaa

           $hdata = $header->data;

       Returns the header data in binary format, appropriate for use in a DNS
       query packet.

COPYRIGHT
       Copyright (c) 1997-2002 Michael Fuhr.

       Portions Copyright (c) 2002-2004 Chris Reinhardt.

       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::Packet,
       Net::DNS::Update, Net::DNS::Question, Net::DNS::RR, RFC 1035 Section
       4.1.1



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