001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  You may obtain a copy of the License at
009     *  
010     *    http://www.apache.org/licenses/LICENSE-2.0
011     *  
012     *  Unless required by applicable law or agreed to in writing,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License. 
018     *  
019     */
020    
021    package org.apache.directory.server.dns.io.encoder;
022    
023    
024    /**
025     * 3. The DNAME Resource Record
026     * 
027     *    The DNAME RR has mnemonic DNAME and type code 39 (decimal).
028     * 
029     *    DNAME has the following format:
030     * 
031     *       <owner> <ttl> <class> DNAME <target>
032     * 
033     *    The format is not class-sensitive.  All fields are required.  The
034     *    RDATA field <target> is a <domain-name> [DNSIS].
035     * 
036     *    The DNAME RR causes type NS additional section processing.
037     * 
038     *    The effect of the DNAME record is the substitution of the record's
039     *    <target> for its <owner> as a suffix of a domain name.  A "no-
040     *    descendants" limitation governs the use of DNAMEs in a zone file:
041     * 
042     *       If a DNAME RR is present at a node N, there may be other data at N
043     *       (except a CNAME or another DNAME), but there MUST be no data at
044     *       any descendant of N.  This restriction applies only to records of
045     *       the same class as the DNAME record.
046     * 
047     *    This rule assures predictable results when a DNAME record is cached
048     *    by a server which is not authoritative for the record's zone.  It
049     *    MUST be enforced when authoritative zone data is loaded.  Together
050     *    with the rules for DNS zone authority [DNSCLR] it implies that DNAME
051     *    and NS records can only coexist at the top of a zone which has only
052     *    one node.
053     * 
054     *    The compression scheme of [DNSIS] MUST NOT be applied to the RDATA
055     *    portion of a DNAME record unless the sending server has some way of
056     *    knowing that the receiver understands the DNAME record format.
057     *    Signalling such understanding is expected to be the subject of future
058     *    DNS Extensions.
059     * 
060     *    Naming loops can be created with DNAME records or a combination of
061     *    DNAME and CNAME records, just as they can with CNAME records alone.
062     *    Resolvers, including resolvers embedded in DNS servers, MUST limit
063     *    the resources they devote to any query.  Implementors should note,
064     *    however, that fairly lengthy chains of DNAME records may be valid.
065     * 
066     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
067     * @version $Rev: 501160 $, $Date: 2007-01-29 21:41:33 +0200 (Mon, 29 Jan 2007) $
068     */
069    public class DnameRecordEncoder
070    {
071    }