Public bug reported: In the example below the local IP 10.0.0.12 UDP port 1234 is DNAT'ed to the local IP 10.0.0.11 port 1234. After sending packets to the DNAT'ed IP/port, packets to the other IP/port never reaches user space on the server.
- On server, add IPs and DNAT rule: ip addr add 10.0.0.11/24 dev <interface> ip addr add 10.0.0.12/24 dev <interface> nft -f - <<EOF table ip dnat-test { chain prerouting { type nat hook prerouting priority dstnat; policy accept; ip daddr 10.0.0.12 udp dport 1234 counter dnat to 10.0.0.11:1234 } } EOF - On server, listen on 10.0.0.11:1234 and reply: echo pong|nc -l -u 10.0.0.11 1234 - On client, send to DNAT'ed 10.0.0.12:1234 and await reply: echo ping|nc -u -p 4321 10.0.0.12 1234 - Ping/pong received on both ends - Terminate nc on both ends and continue before conntrack state timeout - On server, listen on 10.0.0.11:1234 and reply: echo pong|nc -l -u 10.0.0.11 1234 - On client, send to 10.0.0.11:1234 and await reply: echo ping|nc -u -p 4321 10.0.0.11 1234 Expected with kernel 6.8.0-(47..55)-generic: - Ping/pong received on both ends Regression with kernel 6.8.0-(56..60)-generic: - Ping never reaches user space on server, kernel doesn't send ICMP unreachable hinting user space is listening ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: linux-image-6.8.0-59-generic 6.8.0-59.61 ProcVersionSignature: Ubuntu 6.8.0-59.61-generic 6.8.12 Uname: Linux 6.8.0-59-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 May 3 11:22 seq crw-rw---- 1 root audio 116, 33 May 3 11:22 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.28.1-0ubuntu3.5 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/timer', '/dev/snd/seq'] failed with exit code 1: CRDA: N/A CasperMD5CheckResult: pass CurrentDmesg: Error: command ['dmesg'] failed with exit code 1: dmesg: read kernel buffer failed: Operation not permitted Date: Sat May 3 11:27:10 2025 InstallationDate: Installed on 2025-05-02 (1 days ago) InstallationMedia: Ubuntu-Server 24.04.2 LTS "Noble Numbat" - Release amd64 (20250216.2) IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU Tablet Lsusb-t: /: Bus 001.Port 001: Dev 001, Class=root_hub, Driver=uhci_hcd/2p, 12M |__ Port 001: Dev 002, If 0, Class=Human Interface Device, Driver=usbhid, 12M MachineType: QEMU Standard PC (i440FX + PIIX, 1996) PciMultimedia: ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> ProcFB: 0 bochs-drmdrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-6.8.0-59-generic root=/dev/mapper/ubuntu--vg-ubuntu--lv ro RelatedPackageVersions: linux-restricted-modules-6.8.0-59-generic N/A linux-backports-modules-6.8.0-59-generic N/A linux-firmware 20240318.git3b128b60-0ubuntu2.11 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) acpidump: dmi.bios.date: 04/01/2014 dmi.bios.release: 0.0 dmi.bios.vendor: SeaBIOS dmi.bios.version: rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org dmi.chassis.type: 1 dmi.chassis.vendor: QEMU dmi.chassis.version: pc-i440fx-9.2 dmi.modalias: dmi:bvnSeaBIOS:bvrrel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org:bd04/01/2014:br0.0:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-9.2:cvnQEMU:ct1:cvrpc-i440fx-9.2:sku: dmi.product.name: Standard PC (i440FX + PIIX, 1996) dmi.product.version: pc-i440fx-9.2 dmi.sys.vendor: QEMU ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug noble -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2109889 Title: Netfilter DNAT regression with dropped packets in kernel 6.8.0-56 and above Status in linux package in Ubuntu: New Bug description: In the example below the local IP 10.0.0.12 UDP port 1234 is DNAT'ed to the local IP 10.0.0.11 port 1234. After sending packets to the DNAT'ed IP/port, packets to the other IP/port never reaches user space on the server. - On server, add IPs and DNAT rule: ip addr add 10.0.0.11/24 dev <interface> ip addr add 10.0.0.12/24 dev <interface> nft -f - <<EOF table ip dnat-test { chain prerouting { type nat hook prerouting priority dstnat; policy accept; ip daddr 10.0.0.12 udp dport 1234 counter dnat to 10.0.0.11:1234 } } EOF - On server, listen on 10.0.0.11:1234 and reply: echo pong|nc -l -u 10.0.0.11 1234 - On client, send to DNAT'ed 10.0.0.12:1234 and await reply: echo ping|nc -u -p 4321 10.0.0.12 1234 - Ping/pong received on both ends - Terminate nc on both ends and continue before conntrack state timeout - On server, listen on 10.0.0.11:1234 and reply: echo pong|nc -l -u 10.0.0.11 1234 - On client, send to 10.0.0.11:1234 and await reply: echo ping|nc -u -p 4321 10.0.0.11 1234 Expected with kernel 6.8.0-(47..55)-generic: - Ping/pong received on both ends Regression with kernel 6.8.0-(56..60)-generic: - Ping never reaches user space on server, kernel doesn't send ICMP unreachable hinting user space is listening ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: linux-image-6.8.0-59-generic 6.8.0-59.61 ProcVersionSignature: Ubuntu 6.8.0-59.61-generic 6.8.12 Uname: Linux 6.8.0-59-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 May 3 11:22 seq crw-rw---- 1 root audio 116, 33 May 3 11:22 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.28.1-0ubuntu3.5 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/timer', '/dev/snd/seq'] failed with exit code 1: CRDA: N/A CasperMD5CheckResult: pass CurrentDmesg: Error: command ['dmesg'] failed with exit code 1: dmesg: read kernel buffer failed: Operation not permitted Date: Sat May 3 11:27:10 2025 InstallationDate: Installed on 2025-05-02 (1 days ago) InstallationMedia: Ubuntu-Server 24.04.2 LTS "Noble Numbat" - Release amd64 (20250216.2) IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU Tablet Lsusb-t: /: Bus 001.Port 001: Dev 001, Class=root_hub, Driver=uhci_hcd/2p, 12M |__ Port 001: Dev 002, If 0, Class=Human Interface Device, Driver=usbhid, 12M MachineType: QEMU Standard PC (i440FX + PIIX, 1996) PciMultimedia: ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> ProcFB: 0 bochs-drmdrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-6.8.0-59-generic root=/dev/mapper/ubuntu--vg-ubuntu--lv ro RelatedPackageVersions: linux-restricted-modules-6.8.0-59-generic N/A linux-backports-modules-6.8.0-59-generic N/A linux-firmware 20240318.git3b128b60-0ubuntu2.11 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) acpidump: dmi.bios.date: 04/01/2014 dmi.bios.release: 0.0 dmi.bios.vendor: SeaBIOS dmi.bios.version: rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org dmi.chassis.type: 1 dmi.chassis.vendor: QEMU dmi.chassis.version: pc-i440fx-9.2 dmi.modalias: dmi:bvnSeaBIOS:bvrrel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org:bd04/01/2014:br0.0:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-9.2:cvnQEMU:ct1:cvrpc-i440fx-9.2:sku: dmi.product.name: Standard PC (i440FX + PIIX, 1996) dmi.product.version: pc-i440fx-9.2 dmi.sys.vendor: QEMU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2109889/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp