Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.8 kernel[0].
If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'. If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'. Once testing of the upstream kernel is complete, please mark this bug as "Confirmed". Thanks in advance. [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.8-rc6 ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- 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/1622877 Title: MTU probing does not work Status in linux package in Ubuntu: Incomplete Bug description: 1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu Ubuntu 16.04.1 LTS 2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center Kernel version 4.4.0-36 3) What you expected to happen MTU probing should work automatically, there should be no network connectivity problems due to too large MTU. 4) What happened instead I'm having an Ubuntu 16.04 32bit installation running inside Virtualbox, inside Ubuntu 16.04 64bit installation. Let's call the virtualized server as A and the host server as B. B is connected to Internet with static, public IP address. There are no problems in its network connectivity i.e. it can be reached well with any service from Internet. A has been given a static, public IP address. Actually A is using B's network card in connecting, but in my earlier virtual server installations, this hasn't caused any problems. In earlier installations (14.04 and before), there were no problems with network connectivity. Now, in the fresh 16.04.01 32bit installation on A (i.e. virtual host), it seems that MTU is not probed properly. For example, if I'm trying to have a SSH connection from some internet host into A, the SSH connection freezes in "expecting SSH2_MSG_KEX_ECDH_REPLY" phase. I tried manually setting net.ipv4.tcp_mtu_probing value to 1 and also 2, but it did not help. After I manually set the MTU value for lower value, connectivity problems went away. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-36-generic 4.4.0-36.55 ProcVersionSignature: Ubuntu 4.4.0-36.55-generic 4.4.16 Uname: Linux 4.4.0-36-generic i686 AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.4.0-36-generic. AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.1-0ubuntu2.1 Architecture: i386 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/pcmC0D1c', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/controlC0', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Card0.Amixer.info: Error: [Errno 2] No such file or directory: 'amixer' Card0.Amixer.values: Error: [Errno 2] No such file or directory: 'amixer' Date: Tue Sep 13 10:02:55 2016 HibernationDevice: RESUME=UUID=20336914-b62e-40bb-9eb6-463cf6e159c6 IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub MachineType: innotek GmbH VirtualBox ProcFB: 0 vboxdrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-36-generic root=UUID=952c3908-dbd9-48d0-899a-a3a14a678b7b ro splash quiet RelatedPackageVersions: linux-restricted-modules-4.4.0-36-generic N/A linux-backports-modules-4.4.0-36-generic N/A linux-firmware 1.157.3 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/01/2006 dmi.bios.vendor: innotek GmbH dmi.bios.version: VirtualBox dmi.board.name: VirtualBox dmi.board.vendor: Oracle Corporation dmi.board.version: 1.2 dmi.chassis.type: 1 dmi.chassis.vendor: Oracle Corporation dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr: dmi.product.name: VirtualBox dmi.product.version: 1.2 dmi.sys.vendor: innotek GmbH To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1622877/+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
