[FROG] What causes a prefix received from a downstream to be "invalid"?

[Yakov Sh.]

Hi!
Can you check how this prefix advertised from IPv6-only peer? Is advertised next-hop accessible from your dual-stack router? Since provided output shows 'inaccessible' I suspect dual-stack router has no idea how to get to advertised next-hop.


Yakov Sh.
telegram: @darkyman

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, November 9, 2020 11:46 AM, Michael Hohl <hohl at alwyzon.com> wrote:

> Hello FRRouting community,
>
> I've tried to add an IPv6-only downstream to my dual-stack FRRouting-powered
> BGP setup, but for some reason the prefix of that downstream wasn't distributed
> to my upstream ISP. So, I consulted `show bgp summary` and spotted that this is
> the only route which isn't marked as `valid` indicated by a `*`. RPKI isn't
> enabled, otherwise I would have immediately suspected that to cause some prefix
> to be invalid. The only thing that makes this downstream different is that it
> is IPv6-only.
>
> What does it mean that a (received) prefix is considered "invalid"?
>
> Here is the output for `show bgp 2001:XX:YY::`:
>
>     BGP routing table entry for 2001:XX:YY::/48
>     Paths: (1 available, no best path)
>       Not advertised to any peer
>       ZZZZZZ
>         2a0d:f300:0:VVVV::1 (inaccessible) from 2a0d:f300:0:VVVV::1 (193.219.VV.VV)
>           Origin IGP, invalid, external
>           Last update: Mon Nov  9 09:00:00 2020
>
>
> ZZZZZZ ... is the downstreams ASN
> 2001:XX:YY:: ... is the IPv6 prefix the downstream wants to announce
> 2a0d:f300:0:VVVV::1 ... is the IPv6 address used to run the BGP router of the
> downstream
> 193.219.VV.VV ... is the IPv4 address assigned by me to the downstream,
> but he doesn't really use that one
>
> In case the FRRouting version is relevant for this issue, I'm running 7.3.1.
>
> Thanks in advance for any help,
> Michael
>
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