Re: bad AGGREGATOR, AS 0 not allowed

On Wed, Apr 29, 2020 at 05:45:30PM +0200, Marko Cupać wrote:
> Hi,
>
> on 6.6-RELEASE amd64, (sys)patched up to 019_smtpd_exec, I am noticing
> these:
>
> Apr 29 17:23:33 bgp1 bgpd[42338]: neighbor IP.ADD.RE.SS (desc): bad
> AGGREGATOR, AS 0 not allowed, attribute discarded
>
> My bgpd.conf is almost default, announcing my AS to two upstream peers.
>
> I wrote to my peer, they said they are not sending me AS 0, and to clear my
> session.
>
> After 'bgpctl neighbor desc clear' I'm still getting these messages.
>
> Is this related to:
> [https://marc.info/?l=openbsd-tech&m=156510627921885&w=2]
>
> Can I safely disregard this, and wait for next release for these messages to
> disappear?

At the moment this warning as not been removed, so you will see it even in
the next release. It has indeed todo with the fact that AS 0 is not
allowed even in the AGGREGATOR attribute. Now your neighbor is sending you
such an attribute which indicates that their routers do not handle RFC7607
correctly. At the moment there are a handful of prefixes in the DFZ that
are sent with an AGGREGATOR attribute that has AS 0 and this is what
triggers. You normally get the error on the initial sync.
I wanted to make the error better an include ASPATH / prefix but at the
time this problem happens this information is not available. Time to look
at this again so that the finger pointing is more helpful.

--
:wq Claudio