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Re: was bogon filters, now "Brief Segue on 1918"

  • From: Joel Jaeggli
  • Date: Wed Aug 06 11:21:08 2008

Darden, Patrick S. wrote:
Was looking over 1918 again, and for the record I have only run into one
network that follows:

   "If two (or more) organizations follow the address allocation
   specified in this document and then later wish to establish IP
   connectivity with each other, then there is a risk that address
   uniqueness would be violated.  To minimize the risk it is strongly
   recommended that an organization using private IP addresses choose
   *randomly* from the reserved pool of private addresses, when
allocating
   sub-blocks for its internal allocation."

I added the asterisks.


You're supposed to choose ula-v6 /48 prefixs randomly as well... Any bets on whether that routinely happens?


While you're home can probably randomly allocate subnets out of a /8 or /12 for a while without collisions, nobody that's actually building a subnetting plan for a large private network is going to be able to get away with that in v4.

--Patrick Darden


-----Original Message-----
From: Darden, Patrick S. Sent: Wednesday, August 06, 2008 9:19 AM
To: 'Leo Bicknell'; [email protected]
Subject: RE: Is it time to abandon bogon prefix filters?




Yes.  1918 (10/8, 172.16/12, 192.168/16), D, E, reflective (outgoing
mirroring), and as always individual discretion.

--Patrick Darden


-----Original Message-----
From: Leo Bicknell [mailto:[email protected]]
Sent: Wednesday, August 06, 2008 9:10 AM
To: [email protected]
Subject: Is it time to abandon bogon prefix filters?



"Bogon" filters made a lot of sense when most of the Internet was
bogons.  Back when 5% of the IP space was allocated blocking the
other 95% was an extremely useful endevour.  However, by the same
logic as we get to 80-90% used, blocking the 20-10% unused is
reaching diminishing returns; and at the same time the rate in which
new blocks are allocated continues to increase causing more and
more frequent updates.

Have bogon filters outlived their use?  Is it time to recommend people
go to a simpler bogon filter (e.g. no 1918, Class D, Class E) that
doesn't need to be updated as frequently?