[ppml] alternative realities (was PIv6 for legacy holders (/wRSA + efficient use))

Scott Leibrand sleibrand at internap.com
Wed Aug 1 19:30:28 EDT 2007

Paul Vixie wrote:
> if it's a bad thing, then is there also policy work to be done about it?

I'm not sure a hammer is needed here, as I'm not sure this is a nail.

Let's say that a legacy /8 holder like MIT decides to start leasing out 
their IP space to "customers" buying a tunnel, dial-up, or some other 
similar form of connectivity.  Let's say there is sufficient demand for 
IP space that they sign up a number of customers, each receiving a /24 
with their tunnel and announcing it in BGP to their upstreams.  Now 
let's say this kind of behavior causes the routing table to explode.  If 
I'm a DFZ operator who is no longer able to handle all these prefixes, 
my solution is pretty simple: stop accepting /24's carved up out of /8 
allocations.  Doing so would cause me to send traffic to MIT's customers 
via the MIT /8.  That in turn would either mean that the traffic would 
hit MIT's network and then get sent to MIT's customers via their tunnel, 
or it would hit an intermediate network that was listening to the 
more-specific /24 announcement from MIT's customers (probably because 
they're being paid to do so), who would in turn send the traffic along 

In summary, I'm sure this kind of thing will happen as we exhaust the 
IPv4 free pool, but I'm not sure it will break things too badly.


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