"Tactical" /24 announcements

Hank Nussbacher hank at interall.co.il
Mon Aug 9 17:31:57 UTC 2021

On 09/08/2021 18:47, Billy Croan wrote:
> How does the community feel about using /24 originations in BGP as a
> tactical advantage against potential bgp hijackers?
> All of our allocations are larger and those prefixes we announce for
> clients as well usually are.  But we had a request recently to
> originate everything as distinct /24 prefixes, to reduce the effect of
> a potential bgp hijack.  It seemed a little bit like a tragedy of the
> commons situation.
> Is this seen as route table pollution, or a necessary evil in today's world?
> How many routers out there today would be affected if everyone did this?
> Are there any big networks that drop or penalize announcements like this?

In addition to what everyone else said, announcing /24s will not help 
you one bit since ASNs announce /25s, /26s, /27s, etc. Attached is a 
7800+ line text file sorted by ASN with prefixes being announced that 
are more specific than /24 (only /25+/26+/27 listed).

This is based on http://www.ris.ripe.net/dumps/riswhoisdump.IPv4.gz from 
about a month ago.

That dump lists all the IPv4 prefixes seen in the collective of latest 
RIS table dumps, together with origin AS and number of peers that passed 
the routes to RIS.

So good luck with announcing /24s.

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