Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
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-rc3 ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Tags added: kernel-da-key ** Changed in: linux (Ubuntu) Status: Incomplete => Triaged -- 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/1605137 Title: Can still ping container IP address after removing container Status in linux package in Ubuntu: Triaged Bug description: Using version 2.0.3-0ubuntu2~ubuntu16.04.1~ppa1 I created a container, and then put a tagged vlan on top of lxdbr0 so that I can talk to the host and other containers on a second network. I gave the host's lxdbr0.1215 an IP address, and made eth0.1215 in the container also with its own IP address. After removing the container, I can still ping the address on the VLAN! It also responds with duplicates: $ arping -I lxdbr0.1215 192.168.15.20 ARPING 192.168.15.20 from 192.168.15.1 lxdbr0.1215 Unicast reply from 192.168.15.20 [00:16:3E:B1:9B:0C] 0.599ms Unicast reply from 192.168.15.20 [00:16:3E:B1:9B:0C] 0.607ms Unicast reply from 192.168.15.20 [00:16:3E:B1:9B:0C] 0.609ms Unicast reply from 192.168.15.20 [00:16:3E:B1:9B:0C] 0.534ms Unicast reply from 192.168.15.20 [00:16:3E:B1:9B:0C] 0.541ms $ ping 192.168.15.20 PING 192.168.15.20 (192.168.15.20) 56(84) bytes of data. 64 bytes from 192.168.15.20: icmp_seq=1 ttl=64 time=0.108 ms 64 bytes from 192.168.15.20: icmp_seq=1 ttl=64 time=0.126 ms (DUP!) 64 bytes from 192.168.15.20: icmp_seq=1 ttl=64 time=0.144 ms (DUP!) 64 bytes from 192.168.15.20: icmp_seq=2 ttl=64 time=0.051 ms Bizarrely: $ nmap 192.168.15.20 Starting Nmap 7.01 ( https://nmap.org ) at 2016-07-21 19:01 AEST Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn Nmap done: 1 IP address (0 hosts up) scanned in 3.02 seconds (Supplying -Pn shows all ports are closed.) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1605137/+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