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 -----Original Message----- From: Richard Porter [mailto:rich...@pedantictheory.com] Sent: Sunday, December 17, 2017 8:25 PM To: Robert Webb <rw...@ropeguru.com> Cc: nanog@nanog.org Subject: Re: Companies using public IP space owned by others for internal routing Robert, I’ve heard of two cases recently, large companies (non carrier/ISP). One company looking to solve challenge with IPv6 and 6to4 and DNS. Also curious how wide-spread this is? Maybe just the kick in the butt for catching the elusive IPv6 unicorn? ~Richard > On Dec 17, 2017, at 3:30 PM, Robert Webb <rw...@ropeguru.com> wrote: > > Will anyone comment on the practice of large enterprises using non RFC1918 IP > space that other entities are assigned by ARIN for internal routing? > > Just curious as to how wide spread this might be. I just heard of this > happening with a large ISP and never really thought about it until now. > > Robert