Strange entries from AS1 in global table
me at anuragbhatia.com
Sun Aug 4 05:15:57 UTC 2013
I was looking at global IPv4 table and saw some strange entries from AS1.
As per ARIN whois AS1 seems to be with Level3 but I noticed few prefixes of
Brazil based ISP - Netvip
Looking at any prefix in detail, it seems like there are multiple ASNs
announcing same prefix.
E.g 18.104.22.168/24 - is being announced by AS1 as well as AS52931
(Netvip's allocated ASN). Same is true with 22.214.171.124/24,
126.96.36.199/24and so on.
So seems like AS1 acting like a mirror for all announcements of AS52931. To
see who exactly gave "transit" to AS1 by Netvip in Brazil, I checked Oregon
and noticed these routes:
3356 3549 16735 52931 1 i
Seems like AS52931 itself is acting as transit for AS1 (and AS16735 which
seems like a backbone ISP in Brazil) is not filtering these routes further
passing to Level3 (AS3549+AS3356).
I am curious to know what could be possible reason for an ASN like AS1
acting in exact mirror of AS52931? Could it be a case of internal use of
AS1 (assuming it to be private ASN)? May be it's a case of leaked internal
Appreciate your time & answer.
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