[AusNOG] Experiences with RPKI

[Joseph Goldman]

Hi Phil,

  Thanks - I 100% understand the point of best practice of not using 
maxLength and the potential for hijacking, what im most worried about is 
the statement i've been told about 'unused' ROAs affecting used ROAs, 
which just seems counter-intuitive to me, in terms of (as per the 
example given) having ROAs ready for failover or TE purposes.

  This is the RFC im referring to:

https://datatracker.ietf.org/doc/html/rfc9319

Specifically 5.1 which indicates having dormant ROAs available for use, 
but I am being told having any dormant ROAs is grounds for all routes to 
be marked invalid based on stricter validators, which is the answer im 
trying to ascertain right now.

In a failover sense, say for example I am advertising /22 out of my 
Brisbane POP and some /24's out of my Sydney POP, my Sydney POP goes 
down and im no longer originating those /24's, by what i've been told my 
/22 would now become invalid on next check as my /24's are not being 
advertised, even though I have ROAs for the /22 and /24's.

  I believe i've been given somewhat wrong information but they were 
basing it off experiences with other APNIC members, I just dont want to 
end up in a position where our routes are dropped after implementing our 
ROAs, and maintain flexibility to not wait multiple hours before we can 
advertise a new prefix if required.

Thanks,
Joe

------ Original Message ------
From: "Phil Mawson" <phil.mawson at gmail.com>
To: "Joseph Goldman" <joseph at goldman.id.au>
Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net>
Sent: 23/05/2024 3:52:54 PM
Subject: Re: [AusNOG] Experiences with RPKI

>Hi Joe,
>
>First up, well done on working on your RPKI roll out.  Signing your own 
>routes is the most important step you can take to protect your own 
>network.
>
>In regards to using max length, I do advise against that as what it 
>means someone can still hijack one of your un-advertised routes and it 
>would be treated as real.
>
>IE: If you advertise and sign a /19, but have a ROA created for each 
>route up to a /24.  If you are not advertising all of those, a third 
>party could advertise one of our /24s and spoof your ASN and it would 
>be treated as valid on the internet.
>
>APNIC portal make it very easy to create ROAs for your own routes as it 
>has the route table view so it can see what is already publicly 
>advertise.  I recommend looking at that and then signing routes based 
>on that.
>
>DDoS  mitigation providers and ROAs is an interesting topic and not 
>sure the community can agree on what is the best technical solution for 
>that.
>
>Regards,
>Phil
>
>
>>On 23 May 2024, at 3:46 PM, Joseph Goldman <joseph at goldman.id.au> 
>>wrote:
>>
>>G'day list,
>>
>>  In the process of rolling out RPKI - and while I thought I had a good 
>>grasp on everything, there is one niggling piece of information that 
>>I've come against and can't verify. Was hoping people can share their 
>>experiences.
>>
>>  We are only doing our ROA's to begin with and not implementing 
>>validation until later, the initial thought was to create an ROA for 
>>all our 'supernets' and use maxLength to 24 to help cover any prefix 
>>we may want to advertise. We are a much simpler setup, single AS only 
>>and we do advertise many of our ranges down to /24 but not all of 
>>them. I do know of the best practices of not using maxLength based on 
>>a draft rfc doc, but I am personally not super concerned for our 
>>relatively small use-case to the issues brought up in that doc.
>>
>>  Where I have come into trouble is a source (APNIC helpdesk) 
>>indicating that if we have any ROAs that exist for prefixes we are not 
>>directly advertising - it may lend some validators to mark all our 
>>routes as invalid?
>>
>>i.e. say we had /22 ROA, 2x /23 ROAs and 4x /24 ROAs - are currently 
>>advertising the /22 and 2x /24's, so 2x /23's and 2x /24 ROAs are 
>>'unused' in that we are not advertising those specific resources - 
>>would that cause issues with strict validators out in the wild?
>>
>>  My understanding reading through the RFC's is this should not be the 
>>case. If any ROA that matches the prefix for the origin AS exists it 
>>should be valid, regardless of other ROAs signed by the same resource 
>>holder etc.
>>
>>  Matching ROAs to exact advertisements is great, but it seems to lend 
>>itself to much less flexibility in traffic engineering and failover 
>>scenarios - a good scenario is having dormant /24 ROAs for say a DDoS 
>>mitigation service to use when needed, so you dont have to wait for 
>>RPKI propagation before scrubbing kicks in.
>>
>>  Based on your experience, is having all-encompassing (using 
>>maxLength), or unused ROAs an acceptable way to use RPKI or will we 
>>run into issues?
>>
>>All help appreciated :)
>>
>>Thanks,
>>Joe
>>_______________________________________________
>>AusNOG mailing list
>>AusNOG at lists.ausnog.net
>>https://lists.ausnog.net/mailman/listinfo/ausnog
>
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