[ppml] Effects of explosive routing table growth on ISP behavior

Jon Lewis jlewis at lewis.org
Thu Nov 1 14:24:19 EDT 2007

On Thu, 1 Nov 2007, Stephen Sprunk wrote:

> It'd be really nice if someone would produce a tool that would auto-create
> filter lists that would permit N-bit deaggregates of each block assigned by
> the RIRs.  As long as a covering aggregate was announced, each network could
> tune N to keep their routers from falling over.

That's a little hard to automate since not all the RIRs post the necessary 
info in easy to programatically grab ways.  Most do.

Besides, given that the RIR minimum allocations in each /8 are reasonably 
static, do you really need this filter to be regularly auto-generated?  If 
you use the one I posted to nanog a few weeks ago, it'll block all the 
"smaller than minimum"-RIR routes for the /8's known at the time the 
filter was written.  New /8s would get let through down to the default /24 
size.  So it's not like a bogon list, where status changes have to be 
reflected in the filter ASAP or routes get ignored.

The problem is clueless networks deaggregating and not announcing covering 
CIDRs.  There's lots of them.  I'm considering setting up a web site and 
possibly a DNSBL-style DNS zone that would allow people to look up "their 
IP" and see if "their ISP is without clue".  The idea being to make it 
easy for people to realize their web sites, mail servers, whatever are 
being run by networks abusing the DFZ and are at risk of falling off the 
internet when networks start filtering based on RIR minimum allocations.

  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________

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