Troubleshooting a multicast

From FOGProject Wiki
Revision as of 06:28, 27 June 2011 by Itismike (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Taken from this forum thread.


  • On your server open up terminal and kill any running udpcasts by typing
sudo killall udp-sender
  • now run this command
udp-sender --file /opt/fog/log/multicast.log --ttl 1
  • you should see broadcasting control to: and it should be the highest address of the subnet your fogserver is on
  • the line before that should say your fogserver ipaddress and the interface
  • Now boot up 1 client go to your pxe menu and select debug mode. Do this on the same subnet if possible. Type in:
udp-receiver --mcast-rdv-address yourfogserver
  • On your server you should see that 1 client connected and then you can press any key to start the transfer
  • On your client you should see the contents of your multicast log file scrolling by the screen. You can press ctrl-C to stop it.


Hopefully that worked. Now we need to test 2 clients.

  • Run the command on your server again but this time change the --ttl 1 to --ttl 32
  • You will see that this time your broadcast control is 224.0.0.1 this is the multicast address
  • Boot both clients in debug mode and run the client command on each. Once you see that both clients have connected to the server press any key and see if the log file transfers again to both machines this time. If it does not then chances are something is not setup properly in your router possibly routing tables or multicast settings.


If it does work then good lets try one more step

  • On your server run this:
gunzip -c "/images/anyimagename" | /usr/local/sbin/udp-sender --min-receivers 2 --portbase 9000 --interface yourInterface --half-duplex --ttl 32
  • Now boot up 2 clients in debug mode and enter
udp-receiver --portbase 9000 --mcast-rdv-address fogserverIP | partimage -f3 -b restore /dev/sda stdin

you might need to change /dev/sda to your correct harddrive if it's different use fdisk -l to find out

  • If the clients start imaging then it seems that all of your multicast settings are correct and the problem may lie within fog configuration if it doesn't work then you need to check your router settings
Personal tools
FAQs / Troubleshooting