[lacnog] Question about 240/4 space

Mie Jul 24 22:30:12 -03 2019

Hello Jordi, Carlos e Jorge.
Thanks a lot for your input and views on this subject.

Yes, I think one the main things to look at is this need of firmware 
upgrades everywhere and where it has been blocked to be forwarded as 
legitimate packet. But here it comes the first question: Is that the 
situation on all or majority of big vendors or just some of them ?

On the last proposal I have read it is mentioned there by the authors: 
"/The following operating systems support the use of 240.0.0.0/4 as 
unicast, globally reachable address space: Solaris, Linux, Android, 
Apple OSX, Apple IOS, and FreeBSD. This support has existed since    
approximately 2008.  There are some issues with parts of BSD network 
stack that treat Class-E addresses as "invalid".  There are also cases 
of translation (NAT64) where checks reject Class-E addresses and need 
small fixes.  In both cases we have the patches under review for 
FreeBSD.  Four out of the top 5 open source IoT stacks already treat 
240/4 as unicast, with a 3 line patch awaiting submission for the fifth.
...
//Juniper routers block traffic for 240/4 by default, but there has been 
a simple configuration switch to disable that check since 2010, at which 
point they are fully functional."/

One big problem mentioned that remains is about recent versions of 
Microsoft Windows. That would certainly have to be worked out, but in 
the other hand the upgrade is much easier to reach most PCs than a firmware.

I must agree with Carlos mention about an kind 'poor quality IP space' 
due to these various issues that would arise. If that would ever come to 
be a reality it would have to be at some point some level of forced 
retirement of many devices that no longer can receive updates. And 
certainly this type of thing must be accounted on the total cost.

With regards Jordi's mention of a single vendor not willing to do the 
proper updates to support 240/8 I guess that may not be a showstopper, 
but instead just a hindering. Here it comes something interesting: as 
this would be something very apparent and almost impossible to not be 
unnoticed, it would be a lot of damage to those vendors who fail to 
adapt. I mean, it would not be something partial that could or not pass 
unnoticed in some situations like a minor IPv6 of BGP feature not 
working as expected. Obviously this must also be accounted to the total 
cost of making it happen.

Again, my view is that something like this will not hit IPv6 Deployment. 
I think it is happening well lately and will lucky continue to happen 
exponentially for the next years and a optimistic scenario. But in the 
other hand I still believe the dependency of IPv4 will increase in such 
way that in not much time ahead it will start to cause serious growing 
conflicts that will not be restricted to specific companies. As you very 
well know they will still be need for translations even in a 
near-perferct-IPv6 environment/network, some Hosting scenarios and not 
to be forgotten, the new comers as Autonomous Systems that are equally 
important the others mentioned.

To finish, one question that still keeps hitting my mind remains: Who 
had the idea in first place to put a block in a IP space tagged as 
"Future Use" by IANA ? What came to his/her mind to imagine it would 
never be used for unicast ?

Best regards
Fernando Frediani

On 24/07/2019 17:40, Carlos Marcelo Martinez Cagnazzo wrote:
> Hi Fernando,
>
> I’ll be answering in Spanish if that is not a problem.
>
> Es una muy buena pregunta. Resumiendo, el espacio IPv4 240.0.0.0/4 
> está marcado en los registros de IANA como “Uso Futuro”. Esta 
> asignación surge de la Sección 4 de la RFC 1112 
> (https://tools.ietf.org/html/rfc1112). La pregunta es… ¿no podemos 
> re-designar estos 16 /8s como espacio unicast y asignarlos, dado que 
> son tan necesarios?
>
> Es una pregunta muy válida. La RFC 1112 data de 1989, una fecha que 
> parece hoy casi prehistórica. La Internet en 1989 era una red pequeña, 
> limitada a organizaciones de gobierno, universidades, etc.
>
> Yo tengo mi posición personal, y no estoy convencido de que valga la 
> pena. No porque “vaya a demorar el despliegue de IPv6”, sino por otra 
> razón. Este espacio de direcciones, si lo comenzamos a asignar, va a 
> ser un espacio de direccionamiento de calidad inferior.
>
> ¿Porque?
>
> Para poder utilizar 240/4 como espacio unicast hace falta que los 
> fabricantes de equipamiento *todos* actualicen su software y en sus 
> stacks permitan que paquetes en este rango de direcciones sea 
> procesado como unicast. Estoy hoy no es así.
>
> Ahora bien, no alcanza solo con que los fabricantes actualicen su 
> software. TODOS nosotros operadores desde microscópicos a gigantes 
> tenemos que actualizer los softwares y firmwares de TODO nuestro 
> equipamiento para que estos paquetes en la 240/4 sean tratados de 
> igual manera que digamos, los de la 179/8. Todo equipo que hable IP 
> producido en los últimos 30 años va a tener que ser actualizado.
>
> Nuestro historial como industria implementando estos cambios en escala 
> es muy malo. Hasta el día de hoy hay firewalls que descartan paquetes 
> UDP de DNS de mas de 512 bytes (EDNS0 data de 2013), stacks que 
> implementan IPv6 mal, routers que no soportan ciertos elementos de 
> BGP, etc.
>
> Lo que va a pasar es que eventualmente comencemos a asignar espacio de 
> la 240/8, quienes reciban espacio van a tener un servicio de calidad 
> muy muy inferior. Van a tener errores de conexión y timeouts muy 
> difíciles de depurar. Van a tener problemas con sus clientes. Van a 
> tener problemas en conseguir tránsito y peering que soporte esto.
>
> Por este motivo fundamentalmente, no estoy de acuerdo con la 
> propuesta. Sin embargo, la discusión está abierta en el IETF y serán 
> todos más que bienvenidos en enviar sus comentarios a las listas de 
> correo relevantes.
>
> Saludos,
>
> /Carlos
>
>> On Jul 24, 2019, at 4:16 PM, Fernando Frediani <fhfrediani en gmail.com 
>> <mailto:fhfrediani en gmail.com>> wrote:
>>
>> Hello folks
>>
>> I wanted to put a question about this topic in order to learn a bit 
>> deeper into this question from the community who have better 
>> knowledge about it, specially those who have more IETF involvement.
>>
>> The last time I asked why still the 240/4 wasn't turned into usable 
>> /8's to be distributed to all RIRs and therefore to LIRs and 
>> End-users. The explanation I was given at the time was that people 
>> considered it for quiet a while and came to a conclusion that was not 
>> worth the cost of 'changing everything needed to be changed' in order 
>> to make it work as expected. Some have mentioned that some network 
>> firmware had embedded in it to not even forward packets in this IP space.
>> On this basis I wanted also to understand also who was the 'clever' 
>> idea to deny forwarding to this packets in firmware to something 
>> tagged as "Future Use", therefore that had the expectation to be used 
>> one day in the future ?
>>
>> I am asking this because I have been reading some 'yet again' 
>> proposals to make it viable and wanted to understand what are the the 
>> biggest technical challenges to make it viable.
>> If it is true that some firmware have this limitation, and it goes 
>> down to a CPE level I can start understanding the amount of work to 
>> get every single equipment updated to be able to talk to these future 
>> networks. Even in a ISP/Telecom level one thing that comes to mind is 
>> where you have very old and EOF routers still in production and 
>> people refusing to take them our of production, no doubt even if 
>> Network vendors would provide an updated firmware version those 
>> routers would never receive it. Besides that what other big concerns 
>> are in your view ?
>>
>> With regards the points some people frequently raise about that any 
>> extension to IPv4 space is a killer to IPv6 Deployments to come, I 
>> personally refuse to believe in that, at least not in a binary way 
>> was sometimes is preached. I see that regardless the improvements in 
>> IPv6 deployment (which I obviously support and actively practice on 
>> my day by day) I always had the impression that we will live with the 
>> IPv4 internet for at least, in a very optimistic scenario for another 
>> 10 years or more. Recently I read a report about this subject that 
>> mentioned at least another 20 years.
>>
>> And even when it is said that no matter how much IPv4 becomes 
>> available it will never be enough and would be exhausted quiet 
>> quickly (probably true). Well, I would say that if there is any 
>> chance for these 'new' IPv4 to become functional they should never be 
>> intended to be used as they have been in the last decades, but 
>> instead to certain and specific usages as mainly facilitate IPv6 
>> deployment and translation techniques, Hosting and other scenarios 
>> where no-IPv4-at-all is not an option.
>>
>> Appreciate any comments and contributions to make it possible to 
>> understand this subject better.
>>
>> Best regards
>> Fernando Frediani
>>
>>
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