Big providers use NAT to squeeze little ISPs

Michael Dillon michael at
Thu Feb 27 05:24:41 UTC 1997

On Wed, 26 Feb 1997, Karl Denninger wrote:

> The problem comes about when big ISPs filter at /19s *AND* the allocators 
> of space refuse to give ISPs /19s.

I don't think either of these is in danger of happening. I certainly don't
hear anyone complaining that their Ciscos are going to fall over
due to routing table growth and as we all know, there are other big router
boxes very near release that won't have this problem.

As for allocation policies, these are pretty much in the collective hands
of the network operators now. This means it is extremely unlikely that
they will do something that is dumb from an operational point of view.
Note that the only significant event related to this was when RIPE's
allocation policies conflicted with Sprint's filters and it was worked out
to the general benefit of network operators.

The main problem with filters right now is that there isn't enough of
them, i.e. we need more widespread deployment of bogon filters.

Michael Dillon                   -               Internet & ISP Consulting
Memra Software Inc.              -                  Fax: +1-250-546-3049             -               E-mail: michael at

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