ARPA
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... hand, and that different parts of the tree can have different implied
semantics. For example, the IN-ADDR.ARPA domain is organized and
distributed by network ...
... domain name by
HOSTMASTER.SRI-NIC.ARPA. An appreciation for the reasons behind this
design also must take into account the scheme for mail exchanges [RFC-974].
...
... +---------------------+------------------+
| | |
MIL EDU ARPA
| | |
| | |
...
... In this example, the root domain has three immediate subdomains: MIL,
EDU, and ARPA. The LCS.MIT.EDU domain has one immediate subdomain named
...
... hosts and other resources often have several names
that identify the same resource. For example, the names C.ISI.EDU and
USC-ISIC.ARPA both identify the same host. Similarly, in the case of
mailboxes, many organizations provide many names that actually go to the
...
... name server was processing a query with for USC-
ISIC.ARPA, asking for type A information, and had the following resource
records:
...
...
52.0.0.10.IN-ADDR.ARPA IN PTR C.ISI.EDU
...
...
rather than pointing at USC-ISIC.ARPA. Of course, by the robustness
principle, domain software should not fail when presented with CNAME ...
... character string. The octets of the IP address are reversed,
used as name components, and suffixed with "IN-ADDR.ARPA". A
type PTR query is used to get the RR ...
... 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 ...
... A.ISI.EDU. The MIL domain is served by SRI-NIC.ARPA and A.ISI.EDU. The
EDU domain is served by SRI-NIC ...
... 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 ...
... IN-ADDR.ARPA. PTR C.ISI.EDU.
103.0.3.26.IN-ADDR.ARPA. PTR A.ISI.EDU.
A.ISI.EDU. 86400 A 26.3.0.103
...
... is maintained on host SRI-NIC.ARPA, and the responsible party for the
zone is HOSTMASTER@SRI-NIC.ARPA ...
... ARPA, and the responsible party for the
zone is HOSTMASTER@SRI-NIC.ARPA. A key item in the SOA is the 86400
second minimum TTL, which means that all authoritative data in the zone
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 86400 IN A 26.0.0.73 |
| 86400 IN ...
... query was sent to some other server which was not
authoritative for SRI-NIC.ARPA, the response might be:
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 1777 IN A 10.0.0.51 |
| 1777 IN ...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=* |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 86400 IN A 26.0.0.73 |
| A 10.0.0.51 |
...
... | A 10.0.0.51 |
| MX 0 SRI-NIC.ARPA. |
| HINFO DEC-2060 TOPS20 |
+---------------------------------------------------+
...
... query was directed to two name servers which are not
authoritative for SRI-NIC.ARPA, the responses might be:
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=* |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 12345 IN A 26.0.0.73 |
| A 10.0.0.51 |
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=* |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 1290 IN HINFO DEC-2060 TOPS20 |
+---------------------------------------------------+
...
... routing information for the mail destination HOSTMASTER@SRI-NIC.ARPA.
The response from C.ISI.EDU would be:
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=MX |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | SRI-NIC.ARPA. 86400 IN MX 0 SRI-NIC.ARPA ...
... ARPA. 86400 IN MX 0 SRI-NIC.ARPA.|
+---------------------------------------------------+
Authority ...
... +---------------------------------------------------+
Additional | SRI-NIC.ARPA. 86400 IN A 26.0.0.73 |
| A 10.0.0.51 |
...
... +---------------------------------------------------+
Question | QNAME=SRI-NIC.ARPA., QCLASS=IN, QTYPE=NS |
...
... +---------------------------------------------------+
Question | QNAME=SIR-NIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... NIC.ARPA. HOSTMASTER.SRI-NIC.ARPA. |
| 870611 1800 300 604800 86400 |
+---------------------------------------------------+
...
... Additional | A.ISI.EDU. A 26.3.0.103 |
| SRI-NIC.ARPA. A 26.0.0.73 |
| A 10.0.0.51 |
+---------------------------------------------------+
...
... domain, has referred the requester to
servers on A.ISI.EDU and SRI-NIC.ARPA, which it knows are authoritative
for the MIL domain.
...
... QNAME=USC-ISIC.ARPA, QTYPE=A ...
... AA |
+---------------------------------------------------+
Question | QNAME=USC-ISIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... IN, QTYPE=A |
+---------------------------------------------------+
Answer | USC-ISIC.ARPA. 86400 IN CNAME C.ISI.EDU. |
...
... QNAME is authoritative, but does not say anything about whether the data
for C.ISI.EDU is authoritative. This complete reply is possible because
A.ISI.EDU happens to be authoritative for both the ARPA domain where
USC-ISIC.ARPA ...
... ARPA domain where
USC-ISIC.ARPA is found and the ISI.EDU domain where C.ISI.EDU data is
found.
...
... AA |
+---------------------------------------------------+
Question | QNAME=USC-ISIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... IN, QTYPE=A |
+---------------------------------------------------+
Answer | USC-ISIC.ARPA. 86400 IN CNAME C.ISI.EDU. |
...
...
This reply contains an authoritative reply for the alias USC-ISIC.ARPA,
plus a referral to the name servers for ISI.EDU. This sort of reply
isn't very likely given that the query ...
... AA |
+---------------------------------------------------+
Question | QNAME=USC-ISIC.ARPA., QCLASS=IN, QTYPE=A |
+---------------------------------------------------+
...
... IN, QTYPE=A |
+---------------------------------------------------+
Answer | USC-ISIC.ARPA. 86400 IN CNAME C.ISI.EDU. |
...
... The resolver would translate this into a request for PTR RRs for
65.0.6.26.IN-ADDR.ARPA. This information is not in the cache, so the
resolver would look for foreign servers to ask. No servers would match,
...
... domain are in the cache, but ISI.EDU is not an ancestor of
65.0.6.26.IN-ADDR.ARPA, so the SBELT is used.)
...
... AA |
+---------------------------------------------------+
Question | QNAME=65.0.6.26.IN-ADDR.ARPA.,QCLASS=IN,QTYPE=PTR |
+---------------------------------------------------+
...
... IN,QTYPE=PTR |
+---------------------------------------------------+
Answer | 65.0.6.26.IN-ADDR.ARPA. PTR ACC.ARPA. |
+---------------------------------------------------+
...
... +---------------------------------------------------+
Answer | 65.0.6.26.IN-ADDR.ARPA. PTR ACC.ARPA. |
+---------------------------------------------------+
Authority ...