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icon9.gif  Multicast client can't see traffic inside the virtual machine [message #15029] Tue, 17 July 2007 10:36 Go to next message
danielcamara is currently offline  danielcamara
Messages: 8
Registered: July 2007
Location: France
Junior Member
Hi people I don't know what, but for sure something I am doing wrong Smile.

I have the following configuration :
     +=================+      +=================+  
     |  Multicast app  |      |  Multicast app  |  
  ++=|     Server      |      |     Client      |  
  || +-----------------+      +-----------------+  
  || |      eth0       |      |      eth0       |<==++
  || +-----------------+      +-----------------+   ||
  || | Virtual Machine |      | Virtual Machine |   ||
  || |       104       |      |       105       |   ||
  || +=================+      +=================+   ||
  VV          |                        |            ||
--||------------------------------------------------||---     
  ||          |                        |           XXXX
  ||     +-----------+           +-----------+      ||
  ++===> | veth104.0 |           | veth105.0 | ++=>=+    
      ++ +-----------+           +-----------+ ||   
      ||     A                         A       ||    
      ||     |                         |       ||     
      ||     |     +==============+    |       ||     
      ++==>  +-----|    vzbr0     |----+  ===>=++
                   +--------------+                
                   |    eth0      |                
                   +--------------+                
                   | Real Machine |                
                   +==============+         


I have a multicast application that works with broadcast on the address 224.0.0.131. I manage to create the above architecture and pings to both machines, from both machines, work. The three machines, the two virtual and the real one, are in the same network. When I ping the broadcast address, all three machines answer, no problem.

However, when I start the multicast application, in the server, the messages do not reach the eth0 of the client. If I put a tcpdump I can see the messages arriving even at the veth105.0, but not at the eth0 of the Client. Any one has any idea? I followed the how to at http://wiki.openvz.org/Veth. I searched through the Internet a little and found that the problem could be in the redirection, so in plus I enabled /proc/sys/net/ipv4/conf/*/accept_redirects and /proc/sys/net/ipv4/conf/*/send_redirects, and disabled
/proc/sys/net/ipv4/icmp_echo_ignore_all and /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts in both, Real Machine and Client machines. However this also didn't work.

Sorry for bother... but I really must this working and it seems to be so close... seems to be just a configuration or some thing like that, but I really don't have any guesses and I couldn't find more information. Any guesses are welcomed Smile

Best regards...

Daniel Camara
Re: Multicast client can't see traffic inside the virtual machine [message #15116 is a reply to message #15029] Thu, 19 July 2007 09:51 Go to previous messageGo to next message
fcoiffie is currently offline  fcoiffie
Messages: 1
Registered: July 2007
Junior Member
In fact, there were a bug in the OpenVZ kernel about multicast traffic. This problem was recently solved (begin of June). You can found it in the Git repository.
Normally, it should be in the next kernel release : 2.6.20-ovz008.1
Re: Multicast client can't see traffic inside the virtual machine [message #15118 is a reply to message #15029] Thu, 19 July 2007 10:04 Go to previous messageGo to next message
Vasily Tarasov is currently offline  Vasily Tarasov
Messages: 1345
Registered: January 2006
Senior Member
What kernel version do you use?

The problem with multicasts was fixed in 028stab034 kernel...

Vasily
Re: Multicast client can't see traffic inside the virtual machine [message #15121 is a reply to message #15116] Thu, 19 July 2007 12:14 Go to previous messageGo to next message
danielcamara is currently offline  danielcamara
Messages: 8
Registered: July 2007
Location: France
Junior Member
On the real machine:
> uname -a
Linux scoubidou 2.6.18-028stab033.1-ovz-enterprise #1 SMP Thu May 31 04:04:19 CEST 2007 i686 GNU/Linux

Well it seems that can be this Smile I will try and afterwards I will put the result here Smile

Thanks to you both,

Daniel
Re: Multicast client can't see traffic inside the virtual machine [message #15128 is a reply to message #15029] Thu, 19 July 2007 14:58 Go to previous message
danielcamara is currently offline  danielcamara
Messages: 8
Registered: July 2007
Location: France
Junior Member
Yes it was the Open vz version Embarassed sorry for that Sad.

However, without enabling the send_redirects and disabling the icmp_echo_ignore_all and icmp_echo_ignore_broadcasts, it doesn't work. I don't know if the redirect in all interfaces is needed, I didn't have time to test it yet, but any way, at least in this way it works Very Happy. Could be interesting to add some thing like this at the http://wiki.openvz.org/Veth wiki page:
[host-node]# enable () { for file in $@; do echo $file; echo 1 > $file; done }
[host-node]# enable /proc/sys/net/ipv4/conf/*/send_redirects
[host-node]# cat 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all
[host-node]# cat 0 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts


The problem is that I don't know if this is fine for every case, it even maybe cause some trouble to some one. I don't know, what do you think?

Best regards, and thanks again guys, I would get stuck there for a loooooong time prior than thinking in update the kernel Sad

Daniel
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