RFC 5549 - IPv4 Routes with IPv6 next-hop - Does it really exists?

Wed Jul 29 16:43:35 UTC 2020

Does anybody here knows what Gambiarra means?

Alejandro mentioned that IPv6 NextHop on IPv4 routing breaks traceroute and
difficult troubleshooting.

Well... Since a while I have been thinking about a Gambiarra that I'm using
on other scenarios, but I think could help to reduce de bad impacts of IPv6
NextHop on IPv4 routing.

O router with several interfaces with IPv6 only and at least one public
IPv4 /32 on his loopback.
On the IPv4 address on each of that v6 only interfaces, use "IP address
unnumbered loopback 0".

This would make the ICMP responses for TTL expired be sourced with that
public IPv4.

Would not be as good as one public IP for each interface, but at least, on
a traceroute, would be possible to Defined what ASN is responsible for that
hop, and exactly in what router it occurs.

Em qua, 29 de jul de 2020 08:25, Alejandro Acosta <
alejandroacostaalamo at gmail.com> escreveu:

> Long time ago I tried it out:
>
>
> https://blog.acostasite.com/2013/02/publicar-prefijos-ipv4-sobre-una-sesion.html
>
>
> https://blog.acostasite.com/2013/02/publicando-prefijos-ipv6-sobre-sesiones.html
>
>
> I did not like, difficult troubleshooting in case something goes wrong
> (however I can understand it's a nice feature to have and in might be
> useful in some scenarios).
>
>
> But you are right I do not know much about networks doing it, I also would
> like hear about it.
>
>
> Alejandro,
>
>
> On 7/29/20 1:51 AM, Douglas Fischer wrote:
>
> Let's just jump all the arguing about lack of IPv4, the need of IPv6, and
> etc...
>
> I must confess that I don't know all the RFCs.
> I would like it, but I don't!
>
> And today, I reached on https://tools.ietf.org/html/rfc5549
>
> I knew that was possible to transfer v4 routes over v6 BGP sessions, or v6
> routes over v4 BGP sessions.
> But I got surprised when I saw this youtube vídeo of AMS-IX guys
> considering use a v6 only Lan, and doing v6 next-hops to v4 routes.
> https://www.youtube.com/watch?v=uJOtfiHDCMw
>
> Well... I guess that idea didn't go to production.
>
>
>
> But the questions are:
> There is any network that really implements RFC5549?
> Can anyone share some information about it?
>
> --
> Douglas Fernando Fischer
> Engº de Controle e Automação
>
>
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