6. A SCENARIO

In our sample domain space, suppose we wanted separate administrative control for the root, MIL, EDU, MIT.EDU and ISI.EDU zones. We might allocate name servers as follows:

                                   |(C.ISI.EDU,SRI-NIC.ARPA
                                   | A.ISI.EDU)
             +---------------------+------------------+
             |                     |                  |
            MIL                   EDU                ARPA
             |(SRI-NIC.ARPA,       |(SRI-NIC.ARPA,    |
             | A.ISI.EDU           | C.ISI.EDU)       |
       +-----+-----+               |     +------+-----+-----+
       |     |     |               |     |      |           |
      BRL  NOSC  DARPA             |  IN-ADDR  SRI-NIC     ACC
                                   |
       +--------+------------------+---------------+--------+
       |        |                  |               |        |
      UCI      MIT                 |              UDEL     YALE
                |(XX.LCS.MIT.EDU, ISI
                |ACHILLES.MIT.EDU) |(VAXA.ISI.EDU,VENERA.ISI.EDU,
            +---+---+              | A.ISI.EDU)
            |       |              |
           LCS   ACHILLES +--+-----+-----+--------+
            |             |  |     |     |        |
            XX            A  C   VAXA  VENERA Mockapetris

In this example, the authoritative name server is shown in parentheses at the point in the domain tree at which is assumes control.

Thus the root name servers are on C.ISI.EDU, SRI-NIC.ARPA, and A.ISI.EDU. The MIL domain is served by SRI-NIC.ARPA and A.ISI.EDU. The EDU domain is served by SRI-NIC.ARPA. and C.ISI.EDU. Note that servers may have zones which are contiguous or disjoint. In this scenario, C.ISI.EDU has contiguous zones at the root and EDU domains. A.ISI.EDU has contiguous zones at the root and MIL domains, but also has a non- contiguous zone at ISI.EDU.

• 6.1. C.ISI.EDU name server
• 6.2. Example standard queries
  • 6.2.1. QNAME=SRI-NIC.ARPA, QTYPE=A
  • 6.2.2. QNAME=SRI-NIC.ARPA, QTYPE=*
  • 6.2.3. QNAME=SRI-NIC.ARPA, QTYPE=MX
  • 6.2.4. QNAME=SRI-NIC.ARPA, QTYPE=NS
  • 6.2.5. QNAME=SIR-NIC.ARPA, QTYPE=A
  • 6.2.6. QNAME=BRL.MIL, QTYPE=A
  • 6.2.7. QNAME=USC-ISIC.ARPA, QTYPE=A
  • 6.2.8. QNAME=USC-ISIC.ARPA, QTYPE=CNAME
• 6.3. Example resolution
  • 6.3.1. Resolve MX for ISI.EDU.
  • 6.3.2. Get the host name for address 26.6.0.65
  • 6.3.3. Get the host address of poneria.ISI.EDU