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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  
21  package org.apache.directory.server.dns.io.encoder;
22  
23  
24  /**
25   * 3. The DNAME Resource Record
26   * 
27   *    The DNAME RR has mnemonic DNAME and type code 39 (decimal).
28   * 
29   *    DNAME has the following format:
30   * 
31   *       <owner> <ttl> <class> DNAME <target>
32   * 
33   *    The format is not class-sensitive.  All fields are required.  The
34   *    RDATA field <target> is a <domain-name> [DNSIS].
35   * 
36   *    The DNAME RR causes type NS additional section processing.
37   * 
38   *    The effect of the DNAME record is the substitution of the record's
39   *    <target> for its <owner> as a suffix of a domain name.  A "no-
40   *    descendants" limitation governs the use of DNAMEs in a zone file:
41   * 
42   *       If a DNAME RR is present at a node N, there may be other data at N
43   *       (except a CNAME or another DNAME), but there MUST be no data at
44   *       any descendant of N.  This restriction applies only to records of
45   *       the same class as the DNAME record.
46   * 
47   *    This rule assures predictable results when a DNAME record is cached
48   *    by a server which is not authoritative for the record's zone.  It
49   *    MUST be enforced when authoritative zone data is loaded.  Together
50   *    with the rules for DNS zone authority [DNSCLR] it implies that DNAME
51   *    and NS records can only coexist at the top of a zone which has only
52   *    one node.
53   * 
54   *    The compression scheme of [DNSIS] MUST NOT be applied to the RDATA
55   *    portion of a DNAME record unless the sending server has some way of
56   *    knowing that the receiver understands the DNAME record format.
57   *    Signalling such understanding is expected to be the subject of future
58   *    DNS Extensions.
59   * 
60   *    Naming loops can be created with DNAME records or a combination of
61   *    DNAME and CNAME records, just as they can with CNAME records alone.
62   *    Resolvers, including resolvers embedded in DNS servers, MUST limit
63   *    the resources they devote to any query.  Implementors should note,
64   *    however, that fairly lengthy chains of DNAME records may be valid.
65   * 
66   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
67   * @version $Rev: 501160 $, $Date: 2007-01-29 20:41:33 +0100 (Mo, 29 Jan 2007) $
68   */
69  public class DnameRecordEncoder
70  {
71  }