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Re: Draft internic ip allocation doc
From: Vince Fuller <vaf () valinor barrnet net>
Date: Tue, 16 May 95 15:41:43 PDT

    All ISPs receiving /16 prefix blocks from the InterNIC will be responsible
    for maintaining all IN-ADDR.ARPA domain records for their respective
    customers.  The InterNIC Registry will only be responsible for the
    maintenance of IN-ADDR.ARPA domain records for those CIDR blocks with
    prefixes longer than /16 issued directly from the InterNIC.

    I think you mean shorter, as in:

    The InterNIC Registry will only be responsible for the
    maintenance of IN-ADDR.ARPA domain records for those CIDR blocks with
    prefixes SHORTER than /16 issued directly from the InterNIC.  

No, I think he means longer. IN-ADDR.ARPA can only be delegated on octet
boundaries, so IN-ADDR for /16 and shorter prefixes will be delegated in /16
chunks. IN-ADDR for prefixes longer than /16 must still be maintained by the
root, since they cannot be delegated.

For example, assume an ISP has been allocated the prefix 204.160/14. Along with
this, the InterNIC will delegate the corresponding IN-ADDR domains:

        160.204.IN-ADDR.ARPA
        161.204.IN-ADDR.ARPA
        162.204.IN-ADDR.ARPA
        163.204.IN-ADDR.ARPA

If the ISP were instead only assigned 204.160.0/17, the associated IN-ADDR
range would be:

        0.160.204.IN-ADDR.ARPA
        ...
        127.160.204.IN-ADDR.ARPA

which is not octet-aligned and therefore cannot be delegated.

        --Vince


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