Hyper-V platform. 2 VMs with vlan interface couldn't ping each other through VM's vlan interface.

Question

I have created two Linux virtual machines, A and B, on the Hyper-V platform. Both A and B have two interfaces, eth0 and eth1. The eth1 interface of A and B are connected to the same virtual switch (VS1), and they can ping each other successfully. I have also created a VLAN interface (eth1.1) on both A and B's eth1 interface. However, I am unable to ping the eth1.1 IP address of B from A, even though I can ping the eth1 IP address of B from A. After capturing packets on both A and B's eth1 interface, I noticed that there is an ARP request packet with 802.1q tag on A's eth1, but B's eth1 did not receive it. I have tried enabling VLAN identification on VS1, which allows B's eth1 to receive the ARP request from A's eth1, but the 802.1q tag is missing. Can anyone help me understand why the ARP request packet with 802.1q tag is not being forwarded to B's eth1, and how I can resolve this issue?

Answer 1

Hello Thank you for your question and reaching out. I can understand you are having query\issues related to Hyper-V Vms couldn't ping each other through VM's vlan interface Verify that VLAN tagging is supported by your physical NICs and that this capability is turned on. The virtual switch or each individual virtual machine should have the VLAN ID configured, not the real NIC. The management operating system (sometimes referred to as Host or Parent Partition) uses the VLAN ID on the Virtual Switch. Each virtual machine (VM) will use the VLAN ID option found in its settings. NOTE: On the Virtual Switch, a single VLAN ID can only be assigned. The VMs (child partitions) can run on many VLANs, whereas the V-Switch (parent partition) can only work on one VLAN. Disable Internal firewall on both VMs and Check the IP configuration as well, namely the IP address, MASK, and GATEWAY. --If the reply is helpful, please Upvote and Accept as answer--