Small business may have a small routed network (a few router hops), There is no mechanism to propagate PA address withdrawal through a few hops. By the way, it should not be RA lifetime because router may have a few connections to ISPs, not all down at the same time. It should be PIO (specific prefix) on the last hop. Eduard
-----Original Message----- From: Niels Bakker via NANOG <nanog@lists.nanog.org> Sent: Thursday, June 18, 2026 16:22 To: nanog@lists.nanog.org Cc: Niels Bakker <niels=nanog@bakker.net> Subject: Re: IPv4 flag day
* Matthew Petach [Wed 17 Jun 2026, 03:24 CEST]:
Unfortunately, there's nothing that tells the downstream host "hey, stop using that address as a source address for connections".
0 lifetime RAs.
-- Niels.
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