ARPA
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... IP address to host name support. The existing support is
the IN-ADDR.ARPA section of the DNS name space. As a result this RFC
describes one structure for network ...
... create network number to name
entries in IN-ADDR.ARPA domains under his control. Thus, the name
for the ARPANET ...
... domains under his control. Thus, the name
for the ARPANET might become NET.ARPA, ARPANET.ARPA or Arpa-
...
... ARPANET might become NET.ARPA, ARPANET.ARPA or Arpa-
network.MIL., depending on the preferences of the owner.
...
... The same network number slots already assigned and delegated
in the IN-ADDR.ARPA section of the name space. ...
... space is overwhelming and would lead to the WKS syndrome. (As
of February, 1989, approximately 400 sections of the
IN-ADDR.ARPA tree are already delegated, usually at network
...
... method is used for subnets in a nested
fashion. For example, 0.0.0.10.IN-ADDR.ARPA. for net 10.
...
...
0.0.2.128.IN-ADDR.ARPA. PTR cmu-net.cmu.edu.
A 255.255.255.0
...
...
In general, this information will be added to an existing
master file for some IN-ADDR.ARPA domain for each network
...
...
isi-net.isi.edu. PTR 0.0.9.128.IN-ADDR.ARPA.
...
... domain name of the organization; this is a
different file from that which holds the information below
IN-ADDR.ARPA. Similar PTR RRs can be used at subnet names.
...
... The data here is one or more PTR RRs pointing at the
IN-ADDR.ARPA names corresponding to host-zero entries for
networks ...
...
ISI.EDU. PTR 0.0.9.128.IN-ADDR.ARPA.
MCC ...
... MCC.COM. PTR 0.167.5.192.IN-ADDR.ARPA.
PTR 0.168.5.192.IN-ADDR.ARPA.
PTR 0.169.5.192.IN-ADDR.ARPA.
...
... PTR 0.169.5.192.IN-ADDR.ARPA.
PTR 0.0.62.128.IN-ADDR.ARPA.
...
... RRs which
would be added, assuming the ARPANET.ARPA was selected as a network
name, would be:
...
...
ARPA. PTR 0.0.0.10.IN-ADDR.ARPA.
...
...
The first RR states that the organization named ARPA owns net 10 (It
might also own more network numbers, and these would be represented
...
... network
name ARPANET.ARPA. maps to net 10. The last states that net 10 is
named ARPANET.ARPA ...
...
Note that all of the usual host and corresponding IN-ADDR.ARPA
entries would still be required.
...
... ; Define network entry
isi-net.isi.edu. PTR 0.0.9.128.IN-ADDR.ARPA.
; Define first level subnets ...
... subnets
div1-subnet.isi.edu. PTR 0.1.9.128.IN-ADDR.ARPA.
div2-subnet.isi.edu. PTR 0.2.9.128.IN-ADDR.ARPA ...
... IN-ADDR.ARPA.
div2-subnet.isi.edu. PTR 0.2.9.128.IN-ADDR.ARPA.
; Define second level subnets ...
... ; Define second level subnets
inc-subsubnet.isi.edu. PTR 16.2.9.128.IN-ADDR.ARPA.
in the 9.128.IN-ADDR.ARPA ...
... network number and address mask
0.0.9.128.IN-ADDR.ARPA. PTR isi-net.isi.edu.
A 255.255.255.0 ;aka X'FFFFFF00'
...
... ; Define one of the first level subnet numbers and masks
0.1.9.128.IN-ADDR.ARPA. PTR div1-subnet.isi.edu.
A 255.255.255.240 ;aka X'FFFFFFF0'
...
... ; Define another first level subnet number and mask
0.2.9.128.IN-ADDR.ARPA. PTR div2-subnet.isi.edu.
A 255.255.255.240 ;aka X'FFFFFFF0'
...
... ; Define second level subnet number
16.2.9.128.IN-ADDR.ARPA. PTR inc-subsubnet.isi.edu.
...
... high one, two, or three bytes, respectively. Reverse the octets,
suffix IN-ADDR.ARPA, and do a PTR query.
...
... get 10.0.0.0.
2. Construct the name 0.0.0.10.IN-ADDR.ARPA.
3. Do a PTR query ...
... and get 128.9.0.0.
2. Construct the name 0.0.9.128.IN-ADDR.ARPA.
3. Do a PTR query ...
...
1. As before construct a query for 0.0.9.128.IN-ADDR.ARPA.
Retrieve:
...
... Retrieve:
0.0.9.128.IN-ADDR.ARPA. PTR isi-net.isi.edu.
A 255.255.255.0
...
... (255.255.255.0), constructing a query for
0.2.9.128.IN-ADDR.ARPA. Retrieve:
0.2.9.128.IN-ADDR.ARPA ...
... 255.255.255.240 (x'FFFFFFF0'). constructing a query for
16.2.9.128.IN-ADDR.ARPA. Retrieve:
16.2.9.128.IN-ADDR.ARPA ...
... IN-ADDR.ARPA. Retrieve:
16.2.9.128.IN-ADDR.ARPA. PTR inc-subsubnet.isi.edu.
4. Since no A RR ...
... RR, so we build the IN-
ADDR.ARPA YP. Similarly, we could never build an Internet-wide index
of "hosts ...
...
Such a precomputed index is what we mean by YP, and we regard the
IN-ADDR.ARPA domain as the first instance of a YP in the DNS.
...
...
IN-ADDR.Netname.YP. PTR IN-ADDR.ARPA.
...