Autunomous system filtering?

Giuseppe Spanò - Datacast Srl spano at
Fri Nov 18 18:04:33 UTC 2016


We are experiencing a strange issue with announcements from our AS207029.
On Sept. 16th we began to announce our prefixes through our upstream provider AS28716 (E-Planet). Everything worked correctly.

Suddenly during the night between 17th and 18th Sept. the visibility of those prefixes dropped heavily (source: ripe stats) and we began experiencing big issues with our customers. We decided then to differentiate the announcements as it follows:

AS2876 announces
AS207029 announces (those prefixes are idle at the moment)

essentially we split the /22 into two /23 so to keep monitored our AS propagation.
What’s happening is interesting:

prefixes announced by AS2876 are regularly spread everywhere, those announced by AS207029 not.
For example, we can see network from HE looking glasses, but we cannot see it into Cogent, Level3 or Split looking glasses.

It seems an AS filtering is acting somewhere, and this looks a bit weird to me.
Did this ever happen to any of you? Do you have ideas?

Our upstream provider (that owns peering sessions with all the above providers) opened tickets to them, but if Network Engineers from Cogent, Level3 or Split should be reading this, could they kindly have a look into their filter configurations?

Thank you to all of you for your kind attention.


Giuseppe Spanò - Datacast Srl
spano at

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