Companies using public IP space owned by others for internal routing

Matt Hoppes mattlists at
Sun Dec 17 22:33:09 CST 2017

Had a previous employee or I discovered it on the network segment after we had some weird routing issues and had to get that cleaned up. I don't know why anyone would do that when there is tons of private IP space.

> On Dec 17, 2017, at 17:30, Robert Webb <rwebb at> 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

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