[192430] in North American Network Operators' Group
Re: How to find all of an ISP's ASNs
daemon@ATHENA.MIT.EDU (Curtis Doty)
Fri Oct 28 01:31:07 2016
X-Original-To: nanog@nanog.org
In-Reply-To: <c8da21a7-4fdf-d6c8-ba66-9bf748eaaf05@efes.iucc.ac.il>
From: Curtis Doty <Curtis@greenkey.net>
Date: Thu, 27 Oct 2016 14:38:30 -0700
To: Hank Nussbacher <hank@efes.iucc.ac.il>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
On Tue, Oct 25, 2016 at 9:03 PM, Hank Nussbacher <hank@efes.iucc.ac.il>
wrote:
> and if that doesn't work try:
> http://bgp.he.net/AS3356#_graph4
> [replace the ASN with the ASN of your choice to see the interconnections.=
]
>
=E2=80=8BDoesn'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]=3DComcast 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
again. :-(
../C
=E2=80=8B
