Date: Mon, 16 Dec 2024 23:29:07 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 283375] dhclient refuses DHCP offer on FreeBSD 14.1-RELEASE as QEMU/KVM guest with virtio net Message-ID: <bug-283375-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D283375 Bug ID: 283375 Summary: dhclient refuses DHCP offer on FreeBSD 14.1-RELEASE as QEMU/KVM guest with virtio net Product: Base System Version: 14.2-RELEASE Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: mharrodine@gmail.com This is very similar to https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D188990 but that is for = Xen and FreeBSD 10 so I am raising this separately as it affects a different hypervisor in QEMU/KVM. I am observing this same behaviour since upgrading = my host OS to Fedora 41 hence I believe some change occurred on the Linux side where the virtio net driver is now doing or at least trying to or advertisi= ng that it does checksum offloads. Host: Fedora 41 x86_64 fully up to date as at time of writing. Guest: FreeBSD 14.1-RELEASE-p5 GENERIC amd64 Adding `-rxcsum` as in `ifconfig_vtnet0=3D"DHCP -rxcsum"` to /etc/rc.conf resolves the issue. Error on FreeBSD side when running dhclient before above config change: "5 = bad udp checksums in 5 packets" I could see offers being made by dnsmasq-dhcp on the Linux side and was very surprised to tcpdump FreeBSD side and see they were actually received but ignored. Then found the related bug report. I have no issue with disabling rx csums on my guest but it concerns me as a= fan of FreeBSD that this is quite a tricky thing to troubleshoot and a lot of people that might just want to try out FreeBSD might use this very common network configuration on a Linux box (i.e. guest nat networking) and end up frustrated that FreeBSD "doesn't work". Having read the other bug report, I think the solution is not easy and is beyond my simple sysadmin ways to get involved with (happy to help i= f I can though!) but I wanted to report this as I couldn't find an identical re= port and it might affect the priority of the issue overall. --=20 You are receiving this mail because: You are the assignee for the bug.=
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