I recently had a situation where virtual machines on a Windows Server 2016 (WS2016) Hyper-V host could not communicate with each other. Ping tests were failing:<\/p>\n
In this case, I was building a new Windows Server 2016 demo lab for some upcoming community events in The Netherlands and Germany, an updated version of my Hidden Treasures in Hyper-V talk that I\u2019ve done previously at Ignite and TechEd Europe (I doubt I\u2019ll ever do a real talk at Ignite again because I\u2019m neither a MS employee or a conference sponsor). The machine I\u2019m planning on using for these demos is an Intel NUC \u2013 it\u2019s small, powerful, and is built with lots of flash storage. My lab consists of some domain controllers, storage, and some virtualized (nested) hosts, all originally connected to an external vSwitch. I built my new hosts, but could not join them to the domain. I did a ping from the new hosts to the domain controllers, and the tests resulted in massive packet loss. Some packets go through but with 3000+ MS latency.<\/p>\n
At first I thought that I had fat-fingered some IPv4 configurations. But I double and triple checked things. No joy there. And that didn\u2019t make sense (did I mention that this was at while having insomnia at 4am after doing a baby feed?) The usual cause of network problems is VMQ so that was my next suspect. I checked NCPA.CPL for the advanced NIC properties of the Intel NIC and there was no sign of VMQ. That\u2019s not always a confirmation, so I ran Get-NetAdapterAdvancedProperty in PowerShell. My physical NIC did not have VMQ features at all, but the team interface of the virtual switch did<\/em>.<\/p>\n And then I remembered reading that some people found that the team interface (virtual NIC) of the traditional Windows Server (LBFOADMIN) team (not Switch-Embedded Teaming) had VMQ enabled by default and that it caused VMQ-style issues. I ran Set-VMNetAdapterAdvancedProperty to disable the relevant RegistryKeyword for VMQ while running a ping \u2013t and the result was immediate; my virtual switch was now working correctly. I know what you\u2019re thinking \u2013 how can packets switching from one VM to another on the same host be affected by a NIC team? I don\u2019t know, but they randomly are.<\/p>\n I cannot comment on how this affects 10 GbE networking \u2013 the jerks at Chelsio didn\u2019t release WS2016 drivers for the T4 NICs and I cannot justify a spend on new NICs for WinServ work right now (it\u2019s all Azure, all the time these days).\u00a0 But if you are experiencing weird virtual switch packet issues, and you are using a traditional NIC team, then see if VMQ on the team interface (the one connected to your virtual switch) is causing the issue.<\/p>\n","protected":false},"excerpt":{"rendered":" I recently had a situation where virtual machines on a Windows Server 2016 (WS2016) Hyper-V host could not communicate with each other. Ping tests were failing: Extremely high latency Lost packets In this case, I was building a new Windows Server 2016 demo lab for some upcoming community events in The Netherlands and Germany, an … Continue reading “VMQ On Team Interface Breaking Hyper-V Networking”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":18983,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"_wpcom_ai_launchpad_first_post":false,"footnotes":""},"categories":[52],"tags":[181,80,195,137],"class_list":["post-20295","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-windows-server","tag-hyper-v","tag-networking","tag-virtualisation","tag-windows-server-2016"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t