Date: Mon, 16 Feb 2026 20:27:02 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 293227] VNET jail regression on 14-STABLE from 14.3 using bridge and epair Message-ID: <bug-293227-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=293227 Bug ID: 293227 Summary: VNET jail regression on 14-STABLE from 14.3 using bridge and epair Product: Base System Version: 14.3-STABLE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: tom@eborcom.com I am running a recent 14-STABLE (14-n273651-d7207388cc58) and I see a network regression from 14.3-RELEASE running VNET jails using bridge(4) and epair(4). The problem occurs when a client receives data from an IPv6 TCP server running in a VNET jail when the jail has a larger MTU than either the client or another device that packets route through. I noticed this using a wg(4) tunnel with mtu 1420 between the client and server. On 14.3-RELEASE, the jail receives an "ICMP6, packet too big" message which causes it to send smaller packets, but on 14-STABLE the jail repeatedly receives these ICMP messages but does not decrease the size of packets it sends. I first noticed this problem running an nginx server in the jail and curl(1) on the client, but can also reproduce it running nc(1). To reproduce the problem, create a VNET jail using bridge(4) in epair(4), with the bridge and jailed epair interface having IPv6 addresses within the same prefix. The jail host needs the "net.inet6.ip6.forwarding" sysctl set. The client needs to have a smaller mtu that the jail's bridge and epair interfaces, which default to 1500. I notice that 503bf058cd0 was committed to STABLE-14 after 14.3 release to checksum offloading support for epair, but I don't know if this matters. Please let me know if you would like me to run any specific diagnostic commands, test experimental code, or if you need more detail about what I observe. -- You are receiving this mail because: You are the assignee for the bug.home | help
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