North American Network Operators Group
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Re: It's Ars Tech's turn to bang the IPv4 exhaustion drum

  • From: Kevin Loch
  • Date: Tue Aug 19 16:29:28 2008
Randy Bush wrote: 
In practice, many routers require the packet to go twice in the hardware if
the prefix length is > 64 bits, so even though it is a total waste of space,
it is not stupid to use /64 for point-to-point links and even for loopbacks!


some of us remember when we thought similarly for /24s for p2p links,
especially when using rip.

and consider matsuzaki-san's dos vulnerability on a /64 p2p link.  the
prudent operational advice today is to use a /127.


I thought there was an issue with duplicate address detection with /127
(RFC3627)?  /126 should work and lots of folks use /112 which is a more
human-friendly bit boundary.  /112 is also good for multiple access
vlans and just about anything that isn't using autoconfig.

- Kevin