How to find all of an ISP's ASNs
Curtis at greenkey.net
Thu Oct 27 21:38:30 UTC 2016
On Tue, Oct 25, 2016 at 9:03 PM, Hank Nussbacher <hank at efes.iucc.ac.il>
> and if that doesn't work try:
> [replace the ASN with the ASN of your choice to see the interconnections.]
Doesn't always work--as it will only show upstream ASNs.
For example, Comcast's backbone AS interconnects their regional ASNs.
However, the regionals don't show up on http://bgp.he.net/AS7922#_graph4 so
you'd need to find all of them first...with something like
http://bgp.he.net/search?search[search]=Comcast and/or consult your
favorite route server.
Also Gary, keep in mind these aren't static. I.e. new AS are added/removed
over time. And inferred policy (i.e. hub/spoke) could change too.
But I'm still curious...how to you propose to filter by AS?
And what if your neighbor (inside one of those permitted AS) is
compromised? You've just re-exposed your IoT devices' soft white underbelly
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