Companies using public IP space owned by others for internal routing

Scott Morizot tmorizot at
Mon Dec 18 21:09:05 CST 2017

On Sun, Dec 17, 2017 at 8:49 PM, Robert Webb <rwebb at> wrote:

> > From: Mark Andrews [mailto:marka at]
> > > On 18 Dec 2017, at 1:20 pm, Robert Webb <rwebb at> wrote:
> > >
> > > Where I work I have the opposite issue. They have a lot of public IPv4
> > > space and only use it internally never be advertised to the internet.
> > > Something I have never agreed With doing.
> >
> > Why?  This is a perfectly legitimate use of the IP addresses.  The
> purpose of
> > assigning addresses is so that they are unique WORLD WIDE in whatever
> > context you wish to use them in.

> I going to guess you were talking about the use internally of public IP
> addresses..
> But there are rules governing what to use where. So it is OK to hoard
> publicly addressable IPv4 IP's for internal
> use that will never reach the outside world? No the way I have been taught.
> Maybe I just lack that big picture..
I think the big picture here is that they helped fund the development of IP
and received
large enough v4 allocations at the outset that they haven't had to use
kludges like RFC1918
as much as most others have. It's not "hoarding" IPs if you're using them,
whether or
not you choose to advertise and make them accessible to other networks.

It's the world everyone gets to live in with the current version of IP.


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