I have seen AS4100000000 in some routing datasets I am working with, for example Routeviews: AS4100000000

I would like to understand where it is coming from or who controls it so I know how to deal with it, i.e. if I can safely ignore it. My research so far didn't reveal helpful results.

Here is an example of what I did find, there was an announcement but no AS information seems to be available: https://www.cidr-report.org/cgi-bin/as-report?as=4100000000&view=6447 another https://bgp.he.net/AS4100000000

It is not in the bogon/internal use number ranges, so it should be valid but it still seems to be outside of normal use.

I guess the simplest explanation is that this is simply a leak? If that is the case, is there any significance to this number, i.e. why wasn't a number reserved for internal use chosen instead?

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BGPView [1] has it listed as an Austrian company EDV Consulting Zoichter GmbH, but this may also be a glitch in the reporting output owing to it not having a registry entry and reprinting the prior entry.

HE shows that it is originating only a single prefix [2], which looks to be owned by a Polish systems integrator call Atman [3][4]

I suspect that you are right and this is just a leak, by Atman (their real public AS is 24748)[5] and 4100000000 is listed as a peer.

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