February 2026 - Bird-users

How to work with ASPA efficiently?
by Ondřej Caletka 05 Feb '26

05 Feb '26

Hello! I am trying to troubleshoot some ASPA validation failures in BIRD 3.2.0. I wonder whether there is a way how to see a ASPA table entry for particular customer AS number. Something like: bird> show route table aspas all for 2121 syntax error, unexpected NUM, expecting IP4 or IP6 or VPN_RD or CF_SYM_KNOWN I also wonder whether it is possible to filter the data based on the contents of the aspa_provider sets like: bird> show route table aspas all where 3333 ~ aspa_providers Table aspas: Regarding the validation itself, a random trivial example where aspa_check_downstream fails and I don't know why is this: 80.254.230.0/24 bgp_path: 3333 12859 42695 (My ASN is 2121 and there is an ASPA stating that 3333 is provider for 2121) There is no ASPA for 3333 There is ASPA for 12859 not stating 42695 as provider There is ASPA for 42695 not stating 12859 as provider So the up ramp should be 42695 and the down ramp should be 2121 3333 12859 I don't see any valleys here yet it is rejected. Am I doing it wrong? -- Best regards, Ondřej Caletka

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Re: bird 3.2.0 - Malformed AS_PATH attribute - AS_SET segment (1) at 26
by Benjamin LaHaise 04 Feb '26

04 Feb '26

Hello Maria, On Wed, Feb 04, 2026 at 10:23:39PM +0100, Maria Matejka wrote: ... > This is a known feature, mandated by RFC 9774, Section 3: ... > It is still possible to `allow as sets` explicitly, if you really need > to keep them. Ah, so this is a case of the RFCs being ahead of what's actually deployed on the Internet. Sadly, I must accept them as otherwise there are holes in the routing table across a number of providers. If it was just 1 provider then new behaviour could be acceptable. Will have to revisit this in 2 or 3 years to see if ISPs have caught up with RFC 9774. Thank you for the quick response -- it is much appreciated. Cheers, -ben -- "Thought is the essence of where you are now."

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bird 3.2.0 - Malformed AS_PATH attribute - AS_SET segment (1) at 26
by Benjamin LaHaise 04 Feb '26

04 Feb '26

Hello all, 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. Cheers, -ben 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 Feb 4 14:42:49 router bird[24317]: upstream: Malformed AS_PATH attribute - AS_SET segment (1) at 18 Feb 4 14:42:49 router bird[24317]: upstream: Invalid route 204.10.20.0/22 withdrawn 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 213.186.96.0/19 withdrawn Feb 4 14:42:49 router bird[24317]: upstream: Invalid route 94.178.0.0/15 withdrawn Feb 4 14:42:49 router bird[24317]: upstream: Invalid route 37.52.0.0/14 withdrawn Feb 4 14:42:50 router bird[24317]: upstream: Malformed AS_PATH attribute - AS_SET segment (1) at 26 Feb 4 14:42:50 router bird[24317]: upstream: Invalid route 208.68.112.0/21 withdrawn Feb 4 14:42:50 router bird[24317]: upstream: Malformed AS_PATH attribute - AS_SET segment (1) at 18 Feb 4 14:42:50 router bird[24317]: upstream: Invalid route 147.92.87.0/24 withdrawn Feb 4 14:42:50 router bird[24317]: upstream: Invalid route 52.129.48.0/24 withdrawn Feb 4 14:42:50 router bird[24317]: upstream: Malformed AS_PATH attribute - AS_SET segment (1) at 18 Feb 4 14:42:50 router bird[24317]: upstream: Invalid route 15.20.64.0/18 withdrawn -- "Thought is the essence of where you are now."

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