> From: John Curran <jcurran @
> Date: Tue, 22 Mar 1994 00:52:11 -0500
> Subject: Re: RFC 1597
> However, the main goal of the RFC is not to promote firewalls, but
> to provide a realistic alternative for organizations that need very
> large IP network allocations for private network purposes. In the
> absence of private IP network numbers, these organizations could
> consume the remaining IP address space in the next 18 months. By
> providing a privately-numbered alternative, it is hoped that the IPv4
> address space will suffice for a decade or more.
However, once you start to use one of these private network addresses,
you are setting yourself up for renumbering (or worse). In today's
corporate environment, large organizations tend to grow by taking
over other organizations in order to acheive economies of scale.
Having to have firewalls between different parts of the same
orgnaization (to handle the routing) somewhat reduces the advantages
of the merger.
If you consider the example in the RFC of Cash Machines, you can see
that not being able to merge your own cash machine network and that of
an acquired organization would eliminate a significant cost saving.