[j-nsp] Unknown Attribute 28 in BGP

[Einar Bjarni Halldórsson]

Hi,

We have two MX204 edge routers, each with a connection to a different 
upstream provider (and some IXP peerings on both).

Last week the IPv6 transit session on one of them starting flapping. It 
turns out that we got hit with 
https://labs.ripe.net/author/emileaben/unknown-attribute-28-a-source-of-entropy-in-interdomain-routing/

It only happened on one of our edge routers, so I assume for now that 
either our other transit provider filtered the affected route updates, 
or stripped the attribute.

The post from RIPE links to 
https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/topic-map/bgp-error-messages.html 
but I can't see that bgp-error-tolerance helps us, since this type of 
malformed update is always fatal.

Our edge routers are both running Junos 18.2R3-S3.11. I was planning on 
upgrading to 22.2R3 regardless of this error, but it would be nice to 
know that this problem has been fixed in later version, or mitigations 
introduced that can be used.

Anybody know about this problem in particular, or have ideas on 
mitigating malformed BGP updates?

.einar
ISNIC