-----Original Message----- From: Mark Andrews [mailto:marka@isc.org] Sent: Sunday, December 17, 2017 9:35 PM To: Robert Webb <rwebb@ropeguru.com> Cc: Richard Porter <richard@pedantictheory.com>; nanog@nanog.org Subject: Re: Companies using public IP space owned by others for internal routing
On 18 Dec 2017, at 1:20 pm, Robert Webb <rwebb@ropeguru.com> wrote:
Apologies for not responding sooner.
This came to light with me on a forum where someone posted that they thought it strange that their MTA received an IP that is assigned to the DoD DNIC.
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.
Robert
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.
Mark
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.. Robert