Similarly:

Oct  7 20:43:21  rpd[32393]: bgp_read_v4_update:12939: NOTIFICATION sent to 2001:504:27::d1af:0:2 (External AS 53679): code 3 (Update Message Error) subcode 1 (invalid attribute list)


We do have bgp-error-tolerance enabled, however, so in theory, this should throw out update itself, not teardown session.

We’re actually seeing BFD die to route servers as well. 

Any commonality w/ the IX’s below and route server software?
We’re only seeing this on MICE, and v6, FWIW.

Andrew Hoyos
hoyosa@gmail.com



On Oct 7, 2025, at 15:40, Mark Kane <markk@honeycomb.net> wrote:

FWIW, we saw this from rs1/rs2 on a Cisco:

Oct  7 14:49:10 CDT: bgp[1087]: %ROUTING-BGP-3-MALFORM_UPDATE : Malformed UPDATE message received from neighbor 2001:504:27::d1af:0:2 (VRF: default) - message length 171 bytes, error flags 0x00000100, action taken "TreatAsWdr". Error details: "Error 0x00000100, Field "Attr-length", Attribute 35 (Flags 0xe0, Length 1024), Data [f0230400]". NLRIs: [IPv6 Unicast] 2402:2de0::/32
Oct  7 15:18:11 CDT: bgp[1087]: %ROUTING-BGP-3-MALFORM_UPDATE : Malformed UPDATE message received from neighbor 2001:504:27::d1af:0:1 (VRF: default) - message length 171 bytes, error flags 0x00000100, action taken "TreatAsWdr". Error details: "Error 0x00000100, Field "Attr-length", Attribute 35 (Flags 0xe0, Length 1024), Data [f0230400]". NLRIs: [IPv6 Unicast] 2402:2de0::/32

Both sessions have remained up and appear normal.

-----Original Message-----
From: Jay Hanke via mice-discuss <mice-discuss@lists.micemn.net>
Sent: October 7, 2025 15:34
To: Jonathan Stewart <jonathan@les.net>
Cc: mice-discuss@lists.micemn.net
Subject: Re: v6 on rs1/rs2 fubar?

Confirmed at FLIX/CIX-ATL/PIT-IX so far.

All juniper but not all junipers affected

If someone affected can you send me a trace it would be helpful.

On Tue, Oct 7, 2025 at 3:32 PM Jonathan Stewart <jonathan@les.net> wrote:

I've seen BGP sessions resetting this afternoon on Juniper.

What more do we know from the global community?

Jonathan Stewart
Network Engineer
LES.NET - AS18451
Desk: 1-204-666-6191
Mobile: 1-204-990-2120
130 Portage Avenue E
Winnipeg, MB  R3C 0A1
CANADA

On Tue, 2025-10-07 3:11 p.m., Jay Hanke via mice-discuss wrote:
Looks like it might be a worldwide issue.

Running Juniper?

On Tue, Oct 7, 2025 at 3:07 PM Andrew Hoyos <hoyosa@gmail.com>
wrote:
Hi folks,

We dropped v6 to rs1/rs2. Spot checked a few other members we
manage, and same deal.
Any work taking place on route servers at the moment?


Andrew Hoyos
hoyosa@gmail.com



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