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Comment by ipdashc | Hacker News Reader

Cool stuff. Though I've never quite understood how RPKI solves route hijacks. The article says it validates that you're allowed to announce a given prefix outright, but I thought the idea behind a BGP hijack was that you just say you have a good route towards a given prefix, and traffic flows through you as a result?

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There's two kinds of route hijacks. Origin or path based.

RPKI addresses who is allowed to originate a prefix. There are other technical changes that need to be implemented to get path validation, this cloud flare blog has a good write up on the issues/solutions.

https://blog.cloudflare.com/bgp-route-leak-venezuela/

There's another quite good blog from Cloudflare about this here too:

https://blog.cloudflare.com/enforce-first-as-bgp/

RPKI addresses both.

Route Origin Authorizations (ROAs) enforce which ASes are allowed to originate a prefix. ROAs address origin hijacks, and have been around for longer.

Autonomous System Provider Authorizations (ASPAs) enforce which ASes are allowed to be adjacent to each other in an AS_PATH. ASPAs address path hijacks, and were introduced more recently. It used to be that you had to self-host (as in the article) in order to publish ASPAs, but RIRs are now starting to support them on their hosted RPKI offerings. I'm surprised the article didn't mention this as a reason to run your own RPKI.

If the first hop publishes a ROA, and all subsequent hops publish an ASPA, then the full path can be validated.

What's the history and status of ASPA? As far as I can see, it's a fairly active draft with the IETF: https://datatracker.ietf.org/doc/draft-ietf-sidrops-aspa-ver...

It says it's on the standards track, but it's clearly quite new. How well has it been proven out? This page from Hurricane Electric shows <3% adoption: https://bgp.he.net/report/rpki_and_aspa

It's still very early. RIPE and ARIN have only supported publishing them for a few months. ARIN made very little noise about it during the rollout, and many networks are probably still unaware. Give it a couple years, and I expect we'll see fairly good adoption among those already publishing ROAs. There will still be the never-RPKI holdouts, however.

HE publishes their full ASPA table here, if you're interested in digging in: https://routing.he.net/?cmd=display_aspa_table

Note that the first hop has to publish both ROA and ASPA records, as ASPA records describes a set of valid providers.

Also note that ASPA validation prevents only hijack by peers and customers, not by providers. Due to way how ASPA validation works, providers could always announce to their customers routes with valid-looking AS PATH with hijacked ASN appended at its end.

Trust infrastructures are always like this, it's one reason PGP's "Web of trust" doesn't work at scale.

If you trust Alice then it's not astonishing that Alice can stab you in the back. Most of us can probably manage to pick trustworthy direct friends. But then, what if we're to trust that Alice's friends won't betray us ? That's a lot stickier.

PGP tries to distinguish "Do you trust that Alice is who she says she is?" from "Do you trust that Alice is a good judge of character?" but the latter is largely unknowable and PGP treats it as recursive. You trust Alice, Alice trusted Bob, Bob trusted Caroline and now Caroline's friend Dave stabbed you in the back. How is this Alice's fault somehow?

How is that better or worse than the "I trust everyone my authority trusts" mechanism the authority system uses?

Having a handful of authorities means we can direct our limited resources at scrutinizing those authorities. Which we do, to great effect. It's not perfect, such a system will never be perfect, but it keeps improving. It's a lot better in 2026 than it was in 2016, and it was a lot better in 2016 than in 2006. In 1996 this is all new and the CAs have basically no idea what they're doing, what's a domain name? Their employees aren't using Tim's toy hypermedia service, it's for nerds.

The resources available to check that Edith's friend Frank's cousin Gerald is trustworthy are zero and when trusting Gerald goes badly, what do we do? "Oh, huh, be more careful"? It's not actionable at all.

That makes sense, thanks!

RPKI mainly makes the administrative side of the route database more formal and rigorous than previous internet routing registry implementations. The processes for using them to improve network security are discussed at https://manrs.org/

They have a neat dashboard at https://observatory.manrs.org/

The RPKI fix is that any node in a rpki tree is signed by the certificate from the authority above it, all the way up until some root certificate that you trust. So you cannot have some party hijacking a prefix, it would not be signed by its parent authority.

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