Date: Sat, 15 Mar 2025 08:16:39 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 285422] IPv4 source address selection is broken (with loopbacks) Message-ID: <bug-285422-7501-FZLaC62Hr2@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-285422-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-285422-7501@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=285422 --- Comment #3 from Lexi Winter <lexi@hemlock.eden.le-fay.org> --- note that while my example here is a bit contrived, i encountered this problem in real life in a fairly common scenario: - OSPFv3 distributes routers' IPv6 loopback addresses - IPv4 loopback addresses are distributed using IBGP on top of OSPF with BGP extended next hop - FreeBSD receives a BGP advertisement for an IPv4 prefix with an IPV6 next hop - BGP resolves the nexthop of the IPv4 route to a link-local IPv6 address via OSPF, and adds this route to the kernel FIB - FreeBSD cannot ping an address on the IPv4 route because it chooses 0.0.0.0 as the source address. this type of setup (MP-BGP over OSPFv3) is *very* common in modern IP networks, and it's a significant disadvantage of FreeBSD that it can't operate in this environment without assigning the /32 loopback to every IP interface. -- You are receiving this mail because: You are the assignee for the bug.
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