North American Network Operators Group
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Address delegations & filters

  • From: bmanning
  • Date: Thu Sep 28 17:52:03 2000 
Poking about, getting ready for the next in-addr audit, I came across the
following bit of information that may have an effect on those ISPs who
filter based on RIR delegation policy.

If I remember correctly, a common tactic is to filter the traditional
/16 space to ensure that nothing greater than a /16 in announced. For
those folks who do this, there are implications for the following prefixes:

165.0.0.0/16
166.0.0.0/16
167.0.0.0/16
169.0.0.0/16

All of these /16s have portions of the /16 subdelegated as /24s and 
apparently have been this way for some period of time, e.g. pre ARIN.
FWIW.

--bill