We found a number of such instances when working in our last year's Internet Measurements Conference (IMC) paper [1] "A Multi-perspective Analysis of Carrier-Grade NAT Deployment". Back then, spring-summer 2016, we found a number of large cellular ISPs using routable IP address space for their private IP address space. Some cases were AS3651 (Sprint US) AS22140 (T−Mobile US) and AS24608 (H3G SpA IT) among others. We found this practice to be common in other ISPs but we did not have enough data to drive anything conclusive for them. One of the most common blocks was assigned to the UK Ministry of Defense as Shaun also pointed out for Microsoft. You can find the whole discussion is in Section 6.1 and Figure 7. [1] https://arxiv.org/abs/1605.05606 On Mon, Dec 18, 2017 at 2:58 PM, Jason Iannone <jason.iannone@gmail.com> wrote:
My previous employer used 198.18/15 for CE links on IPVPN services. Walgreens used an American SP's space internally and couldn't talk to any users in that space as a result.
On Sun, Dec 17, 2017 at 11:31 PM, Eric Kuhnke <eric.kuhnke@gmail.com> wrote:
some fun examples of the size of ipv6:
https://samsclass.info/ipv6/exhaustion-2016.htm
https://www.reddit.com/r/theydidthemath/comments/2qxgxw/self_just_how_big_is...
On Sun, Dec 17, 2017 at 7:05 PM, Large Hadron Collider < large.hadron.collider@gmx.com> wrote:
Missent.
Welcome to IPv6, where you have technically-reserved-for-future-use space that should never actually need to be used. Quite likely, you can use something like 440::/16 as your private space, but please don't do that unless you've exhausted the true private space.
You're welcome.
On 17/12/2017 14:57, James Downs wrote:
On Dec 17, 2017, at 14:33, Matt Hoppes <mattlists@rivervalleyinternet.net>
wrote:
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.
Unless there isn't.. I've worked at more than one company that had used up all the private space. Then you have the cases where some M&A causes overlapping IP space. In addition, you'd also be surprised how many people just assign the entire 10/8 space into a flat IP space.
-j
-- Narseo Vallina-Rodriguez Research Staff, ICSI Personal web: http://www.icsi.berkeley.edu/~narseo Twitter: https://twitter.com/narseo