Hi!
We experience issues with multicast IP packets not being forwarded by a vSwitch, in ESXi 6.0.0.
On a vSwitch, which has a single port Group inheriting all properties from the vSwitch, we have two VMs. VM A is sending multicast IPv4 packets to VM B over the vSwitch (desitnation address 239.1.1.1). There is no VLAN involved in our config.
Both VMs run a Linux OS. When doing a tcpdump on VM A's interface, we can see the packets leaving VM A. When doing a tcpdump on VM B's interface, these packets are not coming in.
On VM B, we started a small "multicast listener" program, which opens a socket on the interface of interest (eth1) and does an "add Group membership" on this socket. To ensure this is executed correctly, we ran an "ip maddr" command on VM B, and we can see that eth1 has the destination address listed (239.1.1.1).
We also see that when we start this program on VM B, a "tcpdump -ni eth1 igmp" reveals that IGMP Join messages are being sent out by VM B. However they do not reach VM A.
After Reading the information at https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=20447..., I wanted to check if IGMP snooping was enabled. But when using the ESXi Web interface, we can not see any settings about IGMP snooping.
Any help would be appreciated! For example, is there a way to see the real-time status of the "basic MAC filtering" on the vSwitch?
