nanog mailing list archives

Falling for address collection (Was: Evil Bit and Spread Spectrum IP Addressing - NANOG Source Address Shaping)


From: Jason Hellenthal <jhellenthal () dataix net>
Date: Sun, 4 Mar 2012 22:24:23 -0500


Why does everyone keep falling for the same address collector ? ;-)

-- LoL

On Sun, Mar 04, 2012 at 10:22:15AM -0600, Guru NANOG wrote:
Common Misconception: One additional bit of IPv4 Addressing will solve
world hunger

The Evil Bit (or spare unused bit) can be used to store (restore) one bit

The Left-Most bit of the 32-bit Source Address Field can be SET to
Zero no matter what the original value. The Evil bit can be set IFF
the Left-Most bit is **changed**.

Setting the Left-Most bit to zero **folds** this table in half.
http://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.txt

Setting the Left-Most bit to ONE would move return traffic to the
upper half of the Spectrum which has vast quantities of unused /8s

Wide-spread consensus shows that TWO bits can work. Three bits folds
the table to 1/8th.
Governments want a 4-bit Return Prefix to their Super-Hubs for
IPv6-like intercept.

The U.S.FCC is expected to issue the regulations on how Spread
Spectrum Source Address Shaping will work in their licensed CPE
wireless devices. There are 160-bits
in the deprecated header so there are many ways to go.

One-Way Broadcast IP Addressing is now available. The Source Address
Field is used
for the second half of the 64-bit Destination Address. The DF (Did
Flip) bit near the Evil
Bit is used to note the two halves of the Destination Address have
been *flipped*.
NANOGers simply route 32 and then 32 after the flip based only on the
Destination Field.
There is no Source Address, only a channel (port).

Keywords: WRT DNSMASQ Tomato WIFI Linux CPE

-- 
;s =;


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