"Tactical" /24 announcements

William Herrin bill at herrin.us
Mon Aug 9 16:08:42 UTC 2021

On Mon, Aug 9, 2021 at 8:48 AM Billy Croan <BCroan at unrealservers.net> wrote:
> How does the community feel about using /24 originations in BGP as a
> tactical advantage against potential bgp hijackers?
> How many routers out there today would be affected if everyone did this?

Hi Billy,

I did some math on this years ago and it worked out to about 8.5
million IPv4 routes. That's 10 times the current table size, more than
any big-iron router can handle today. If everybody did it, it'd crash
the Internet.

> Is this seen as route table pollution, or a necessary evil in today's world?

Pollution. And it won't save you from a hijack either, since your
adversary's /24 routes will compete and win for at least part of the

> Are there any big networks that drop or penalize announcements like this?

Not in an automated way. Which is bad news for you if you do this
because it means getting folks to -undo- the restrictions they
manually enforce on your specific address space is nearly impossible.

Bill Herrin

William Herrin
bill at herrin.us

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