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      • 15. Re: Vsphere ESXi 6.5 external network connectivity lost on DL380Gen8
        prashant_s Novice

        But are you losing connectivity? because mine was packet drop, there is no connectivity issue.


        If you are losing connectivity, does the connectivity lose if you change the jumbo frame?


        if you dont change the MTU, you are able to connect properly?


        We should be able to change the MTU in network card, but what is the config on the switch port? Is it supporting the changed MTU?

        • 16. Re: Vsphere ESXi 6.5 external network connectivity lost on DL380Gen8
          snamidro Lurker

          To resume :


          ESXI 6.5


          I have a guest with two network card.
          One with E1000 on Vswitch1 with nic0 (mtu 1500)

          One with VMXNet3 on Vswitch2 with nic1 (mtu 9000)


          The MTU is OK on the each nic and vswitch.



          [root@ESXI2:~] esxcfg-vswitch  -l

          Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks

          vSwitch0         1536        5           128               1500    vmnic0


            PortGroup Name        VLAN ID  Used Ports  Uplinks

            VM Network            0        1           vmnic0

            Management Network    0        1           vmnic0


          Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks

          HA               1536        4           1024              9000    vmnic1


            PortGroup Name        VLAN ID  Used Ports  Uplinks

            HA                    0        1           vmnic1


          [root@ESXI2:~] esxcfg-nics -l

          Name    PCI          Driver      Link Speed      Duplex MAC Address       MTU    Description

          vmnic0  0000:03:00.0 tg3         Up   1000Mbps   Full   a0:b3:cc:df:1c:9f 1500   Broadcom Corporation NetXtreme BCM5723 Gigabit Ethernet

          vmnic1  0000:02:00.0 r8168       Up   1000Mbps   Full   00:e0:4c:80:1a:50 9000   Realtek Semiconductor Co., Ltd. RTL8111/8168 PCI Express Gigabit Ethernet controller






          My guest is working with these setting, but jumbo frames are not enabled. Ping working fine on each IP.
          So i want to enable on the second card, because MTU 9000 is set.


          When i set MTU 9000 on this card on the guest, the guest reboot, and the setting is not kept.

          I lose ping because guest reboot, and ping is OK after reboot finished....

          So i would like to know why when i change MTU, the guest reboot ? It's a bug ?

          I don't use the good way ?


          my Broadcom doesnt support MTU 9000, i know. But Realtek is ok. I have same card on another machine not with ESXI and no problem.


          PS: I disabled ipV6 too on vswitch.


          I have some doubt about my vmkernel :



          [root@ESXI2:~] esxcfg-vmknic -l

          Interface  Port Group/DVPort/Opaque Network        IP Family IP Address                              Netmask         Broadcast       MAC Address       MTU     TSO MSS   Enabled Type                NetStack

          vmk0       Management Network                      IPv4                    00:e0:4c:80:1a:50 1500    65535     true    STATIC              defaultTcpipStack





          Logs from ESXI when i change MTU on guest :


          2017-06-23T20:35:15.284Z cpu1:88725)Vmxnet3: 17265: Disable Rx queuing; queue size 256 is larger than Vmxnet3RxQueueLimit limit of 64.

          2017-06-23T20:35:15.284Z cpu1:88725)Vmxnet3: 17623: Using default queue delivery for vmxnet3 for port 0x3000007

          2017-06-23T20:35:15.284Z cpu1:88725)NetPort: 1660: enabled port 0x3000007 with mac 00:0c:29:44:93:21

          2017-06-23T20:35:18.218Z cpu0:66070)Uplink: 4622: vmnic0: Non TSO L2 payload size exceeds uplink MTU. FrameLen: 9014, L3 header offset: 14

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