Hello Benjamin, On Wed, Feb 04, 2026 at 03:52:27PM -0500, Benjamin LaHaise wrote:
> With Fedora 43's bird 3.2.0-1 rpm installed on an x86_64 system, I'm > seeing that several routes are being dropped from a full feed with the log > messages below. Using Fedora's bird 3.1.4-1 does not seem to have any > issues with the same BGP config and peer. Is this a known bug? What > additional information can I provide to aid in the debugging? This is a > backup transit connection that is not yet in full production use (but will > be soon), so I can help with debugging and testing for now. > Feb 4 14:42:49 router bird[24317]: upstream: Malformed AS_PATH attribute - > AS_SET segment (1) at 14 > Feb 4 14:42:49 router bird[24317]: upstream: Invalid route 76.165.0.0/16 > withdrawn This is a known feature, mandated by RFC 9774, Section 3: > Unless explicitly configured by a network operator to do otherwise (e.g., > during a transition phase), BGP speakers: > > - MUST NOT advertise BGP UPDATE messages containing AS_SETs or AS_CONFED_SETs > and > - MUST use the "treat-as-withdraw" error handling behavior per [RFC7606] upon > reception of BGP UPDATE messages containing AS_SETs or AS_CONFED_SETs in the > AS_PATH or AS4_PATH [RFC6793].Per the above specifications, this document > updates [RFC4271] and [RFC5065] by deprecating AS_SET (see [RFC4271], Section > 4.3) and AS_CONFED_SET (see [RFC5065], Section 3), respectively. It is still possible to `allow as sets` explicitly, if you really need to keep them. Maria -- Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.
