Re: Newbie Needs Help: someone is announcing less-specific IPv6 (BGP) route on top of me

[Marco Moock via NANOG <nanog () lists nanog org>]

Am 30.08.2025 um 18:54:15 Uhr schrieb nanog--- via NANOG:

> 2400::/12 is larger than any prefix allocated to a network. In fact
> it's a prefix allocated to ARIN, which sub-allocates prefixes to
> various North American networks.

Isn't 2400::/16 used in the APNIC area?
Various Asian countries use networks in that area.

According to whois, 2400::/20 is allocated to South Korea.

KRNIC is not an ISP but a National Internet Registry similar to APNIC.
 
[ Network Information ]
IPv6 Address       : 2400:0000::/20
Organization Name  : Korea Telecom
Service Name       : KORNET
Address            : Gyeonggi-do Bundang-gu, Seongnam-si Buljeong-ro 90
Zip Code           : 13606
Registration Date  : 20050601
 
Name               : IP Manager
Phone              : +82-2-500-6630
E-Mail             : kornet_ip () kt com
 
 
- KISA/KRNIC WHOIS Service -

> Network operators can announce whatever they want to their customers.
> It's not uncommon for some customers to get summarized routes. Some
> ISP far away from America could be telling its customers "yes, I know
> how to get to North America".

Summarizing routes is different to that - not all prefixes from that
net are announced.

> This radar tool seems to be showing what ISPs tell it, without
> filtering such ISP-specific routes. You can see other "invalid"
> routes such as /128 routes in the same tool. Such routes won't
> propagate across the whole internet, by convention, but there's no
> rule that a single ISP can't use them.

Do they use that to reduce the amount of routing table entries in
routers that are far away from such networks?

-- 
Gruß
Marco

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