Multicast traffic problem

[alamintech]

ISSUE TYPE

• Improvement Request

COMPONENT NAME

UI

CLOUDSTACK VERSION

ACS 4.18.0.0

CONFIGURATION

OS / ENVIRONMENT

AlmaLinux8 MGMT+KVM

SUMMARY

Needed multicast traffic to send or receive from user vm to vm.

STEPS TO REPRODUCE

I am not sure how to reproduce

EXPECTED RESULTS

Esxi system have this option like IGMP
As like below link
https://prnt.sc/e_f5V9S3xgox

ACTUAL RESULTS

[levindecaro]

@alamintech , can you describe your network setup (eg: physical network, L2, VLAN, interface) and screen dump of your guest network / vpc etc. I couldn't see any problem using multicast in KVM environment in SAME guest network.

[alamintech]

Thanks for your reply,
How can I test it from my existing environment? I think your are right I am wrong.
Windows vm to vm or Linux vm to vm(How can test it? is it properly working)

My network like below:

Thank you!

[alamintech]

I am using this guide, https://salmannaqvi.com/2016/11/14/simple-multicast-testing-tool-for-windows/

[levindecaro]

@alamintech From your illustration, you are using a shared L2 networking for guest network right?, did you try the do multicasting on the host first, some switch default blocks multicast. U can try https://github.com/troglobit/mcjoin/ and tcpdump see if you can capture multicast on receiver ends.

[levindecaro]

@alamintech one thing u can try is turn off multicast snooping on bridge interface. Run the vm run on same KVM host first to ensure bridge interface is forwarding multicast.

eg:
echo 0 > /sys/class/net/cloudbr0/bridge/multicast_snooping
echo 2 > /sys/class/net/cloudbr0/bridge/multicast_router

[alamintech]

@alamintech one thing u can try is turn off multicast snooping on bridge interface. Run the vm run on same KVM host first to ensure bridge interface is forwarding multicast.

eg: echo 0 > /sys/class/net/cloudbr0/bridge/multicast_snooping echo 2 > /sys/class/net/cloudbr0/bridge/multicast_router

I follow your step, now needed any service restart ? I see same result no traffic

[alamintech]

This is my kvm server, I see multicast start ip address but not ping from this server. Please see my image below.

[levindecaro]

@alamintech I'd tried your setup, can't see any problem with all default setting, it looks doesn't related ACS nor KVM. Suggest you to try wireshark/tcpdump tools to diagnostic the problem at the first place, it can be windows firewall setting..etc.

[NuxRo]

@levindecaro @alamintech it should have been specified in the original posting that we are dealing with a Security Group zone! It's the SGs who are stopping that traffic, it would have saved time on all the testing above.

@alamintech if it helps, the up and coming 4.18.1 will allow you to create an empty L2 network in a SG zone, you could connect both your VMs into such a net and do your thing there.

[alamintech]

My setup is basic zone, not impact SG.

[levindecaro]

@alamintech , try this on your host

iptables -I FORWARD -m pkttype --pkt-type multicast -j ACCEPT

[alamintech]

iptables not enable from my kvm host.

[alamintech]

now ACS 4.18.1 version is running, This version is enable IGMP by default? or any other settings needed. Thanks.

[alamintech]

Linux server is ok multicast, but when use windows 7 then not REV and SEND packet. Please help me

[alamintech]

I see windows 7 can send multicast packet to outside, but not incoming traffic come to vm.