UNSOLVED Multicast doesn't start

  • I have a problem with multicast. I have proved it in two virtual machines in the same physical pc as the fog server. I have proved with udp-sender and udp-receiver in two physical pc’s in a switch of the LAN and it worked, but when I put the task to work, both pcs stop waiting for the packets to come.
    in multicast logs says: "problem getting data from client: operation not supported .
    Any ideas?

  • Senior Developer

    @amadrigal Just want to bring up my initial thought about maybe OpenVZ not being able to properly handle multicast in the first place. Can you try setting up another test FOG server as KVM instance just to rule out that possible issue!?

  • Moderator

    @amadrigal I reread your thread again to make sure I did not mention this since I see you have pfsense. I did a proof of concept tutorial about using pfsense as igmp proxy here: https://forums.fogproject.org/topic/10117/fog-casting-across-vlans-subnets

    On my task list for today is to setup my sandbox servers to test a few things with FOG 1.5.0, pxe booting, and multicasting. I will run through my tutorial on fog casting to ensure its still accurate. I’ll let you know if I run into any problems. I’m going to use centos 7, fog 1.5.0, pfsense 2.4.2.

  • @george1421 thanks for the help. I think the problem is something related to this igmp proxy. I am now trying to clone by multicast two virtual machines that receive an 192.168.1.x ip from the dhcp in a pfsense box. The fog server is a container in proxmox. The error says something about ip , and that is the pfsense interface, so I installed igmp proxy in pfsense , I have the 2.3 version., but it is still failing. This is the configuration just for the lan, if it works, i’ll put the rest of the vlans later ¿there is something wrong with it?

  • Senior Developer

    @amadrigal said in Multicast doesn't start:

    The clients are in vmbr2

    But the is set for vmbr1 in the screenshot?!

    FOG is made to be setup/installed with one single network interface to do all the things like web ui, NFS upload and multicast deploy. From what I read between the lines you want to split that into two different network segments. Might be possible to do by manual configuration but it can cause trouble as we see. Take a look at the FOG settings in the web UI and play with the multicast interface settings. Be aware this is a special setup.

  • Moderator

    I’ve been loosely following this thread.

    I can tell you a few things.

    1. Routers by default do not forward ip class D (igmp) packets by default. You must specifically allow this on your firewall/router. Even if you have the screening rules in place some routers will not forward igmp messages.

    2. Some routers require a igmp proxy service running. This service will function much like the dhcp-relay/dhcp-helper service. The igmp proxy service will listen on its upstream interface (the interface connected to the same subnet/vlan as the FOG server) and then rebroadcast the igmp stream to any device connected to its listening interfaces. The igmp proxy service will only forward igmp traffic if it has an upstream igmp channel and then a subscriber on its listing interface.

    3. If you have an extended network (multiple routers between the fog server and target computers), you will need this igmp helper service on each router, with the defined upstream interface set towards the subnet where your FOG server is.

    4. The igmp imaging process uses 3 igmp ports. for control, and (I think ??) as the data channel.

  • @sebastian-roth The clients are in vmbr2

  • Senior Developer

    @amadrigal Several different VLANs/subnets, aha. Well that addr a lot more complexity and traps. Where exactly are the clients located in that network?

  • @sebastian-roth thanks for the help. I have been looking at the thread you told me and put a multicast route in my proxmox , but it doesnt work.
    The network is this way: I have several physical interfaces, but only two of them are implied.
    The first one is physically plugged to a fiber route, and is the one used to get to the internal apache servers. Now in proxmox is eth2, bridged by vmbr1, ip, gateway which is the fiber router.
    The second one, is the one that gets to the internal network with about 40 different vlans. it is eth1 uses bridge vmbr2.
    The fog server has an ip for each vlan.
    This picture is from de proxmox server, is the multicast route right?

  • Senior Developer

    @amadrigal It’s been a while since I last used OpenVZ but I do remember it being a bit tricky at times. How is network being setup for this machine?! Possibly OpenVZ just cannot handle multicast properly?!?


  • @amadrigal We need to know your FOG Version please.