[ppml] public addresses for private networks

Lee Howard lee.howard at mci.com
Fri Aug 15 13:14:08 EDT 2003

You make a good point that I have also encountered. . . .

Let's say I set up an internet to interconnect all of the baked-goods
industry.  Some of those Hostess stores may also have Internet 
connections.  If one router at a bakery has a connection to the
Baked Goods Network and a connection to the Internet, the addresses
between BGN and the Internet must not conflict.

We can't use RFC1918 space, because there are millions of bakeries
on the BGN and we've used up all of that space.  Or because Hostess
and Little Debbie both refused to renumber from their space, so we've
already NATed them (I find this justification debatable).

One proposal I've seen at the IETF is:
This suggests an additional network reservation of a /8 for numbering
private provider networks.  The idea as I understand it is for each
organization to use RFC1918 space internally, but the interconnections
would be numbered from this new space.

I am agnostic on this draft, I merely point out its existence.


On Wed, 13 Aug 2003, Bill Van Emburg wrote:

> Date: Wed, 13 Aug 2003 21:53:00 -0400
> From: Bill Van Emburg <arin-member at quadrix.com>
> To: ppml at arin.net
> Subject: Re: [ppml] POC verification process
> What each of you who is following an argument similar to Ian's appears
> to be missing is that it is a very real problem for enterprises that are
> interconnected to avoid conflicting IP space, even within RFC 1918
> addresses.  In any case, they certainly don't globally coordinate their
> use of the private IP space.
> It is also not possible to simply grab a slice of public IP space, even
> though the networks involved will not connect to the Internet.  This is
> because the enterprise would lose the ability to communicate with a
> piece of the Internet, since they would be routing that slice of
> addresses to a private network instead.
> At a previous venture, we used a slice of public IP space assigned to us
> for a network that would never see Internet-routed packets.  The reason
> for this was that we were interconnecting the private networks of
> multiple customers.  Each customer made use of the private IP space, and
> their various uses of it conflicted with each other.  All of them needed
> to get packets to our back end network.  The only way to ensure that a
> conflict of addressing could be avoided was to use addresses that would
> never be used on any customer's private network, and that would never
> need to be routed from our own internal network to the Internet.  The
> only way to do *that* is with a slice of public IP space that we *know*
> is never going to be used by anyone else -- one that we had assigned to us.
> Do you understand the issue?  I happen to think that the idea presented
> here is an excellent one, as it handles one of the largest examples of
> such a case.  I would venture to guess that I was not the first one to
> think of doing as we did in my example above....

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