Multicast in HyperV

Question

Multicast Not Working with VMs on Single Host/Logical Switch

Hello,

I’m facing an issue with multicast traffic in my Hyper-V environment and would appreciate some insights.

I have IGMP snooping enabled, and I’ve noticed the following behavior:

• Multicast works when VMs are on different hosts.
• Multicast also works when VMs are on different logical switches.
• However, multicast does not work when VMs are on the same host or using the same logical switch.

Could someone help explain why multicast is not functioning in the latter scenario? Are there specific configurations or settings I should check in Hyper-V or SCVMM that could affect multicast traffic when VMs are on the same host or logical switch?

Thank you for your assistance!

Answer 1

HI pls follow this steps :

IGMP Snooping Configuration:-

• Ensure that IGMP snooping is correctly configured on the virtual switch. Check that it's enabled on the logical switch settings.
• Confirm that IGMP version settings (IGMPv2 or IGMPv3) are consistent across the network devices and the Hyper-V virtual switch.

2. Virtual Switch Settings

• Verify that the virtual switch where the VMs are connected allows multicast traffic. Check the settings for any policies that might restrict multicast traffic.
• If you are using a Software Load Balancer or similar, ensure that it is configured to handle multicast appropriately.

3. Network Adapter Configuration

• Check the network adapter settings of the VMs. Ensure that the network adapters are configured to use the correct virtual switch and that any features (like VLAN tagging) are set correctly.

4. Windows Firewall Settings

• Ensure that the Windows Firewall on the VMs allows multicast traffic. You may need to create specific inbound and outbound rules for the required multicast addresses and ports.

5. Check for Network Isolation

• If network isolation features are enabled on the logical switch, this may affect multicast traffic. Verify if any isolation settings could be blocking multicast packets between VMs on the same host.

6. Review Hyper-V Host Configuration

• Check the Hyper-V host's network configuration to ensure there are no restrictions or settings that could impede multicast traffic. IGMP Snooping Configuration
  • Ensure that IGMP snooping is correctly configured on the virtual switch. Check that it's enabled on the logical switch settings.
  • Confirm that IGMP version settings (IGMPv2 or IGMPv3) are consistent across the network devices and the Hyper-V virtual switch.
  2. Virtual Switch Settings
  • Verify that the virtual switch where the VMs are connected allows multicast traffic. Check the settings for any policies that might restrict multicast traffic.
  • If you are using a Software Load Balancer or similar, ensure that it is configured to handle multicast appropriately.
  3. Network Adapter Configuration
  • Check the network adapter settings of the VMs. Ensure that the network adapters are configured to use the correct virtual switch and that any features (like VLAN tagging) are set correctly.
  4. Windows Firewall Settings
  • Ensure that the Windows Firewall on the VMs allows multicast traffic. You may need to create specific inbound and outbound rules for the required multicast addresses and ports.
  5. Check for Network Isolation
  • If network isolation features are enabled on the logical switch, this may affect multicast traffic. Verify if any isolation settings could be blocking multicast packets between VMs on the same host.
  6. Review Hyper-V Host Configuration
  • Check the Hyper-V host's network configuration to ensure there are no restrictions or settings that could impede multicast traffic.