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New Member

Invalid traffic from multicast issue again.

Hi All

I am here with this question again because I still have the errors thrown up at me every second.

The following errors:

2003 Jul 02 09:31:41 BST +01:00 %SYS-4-P2_WARN: 1/Invalid traffic from multicast

source address 45:00:00:56:1d:90 on port 1/2

2003 Jul 02 10:03:05 BST +01:00 %SYS-4-P2_WARN: 1/Invalid traffic from multicast

source address 45:00:00:c0:45:b1 on port 1/2

come up on our Cat 4006 Cat OS 6.3.9. time and time again.

As I dont have a probe attached to it direclty, I am not able to take a data capture. Trying to use RSPAN down to the Cat6509 does not work.

Please I need help in know where this is coming from and how to solve it or take a good capture to know which node it is coming from.


  • Other Network Infrastructure Subjects

Re: Invalid traffic from multicast issue again.


this is a tough problem generally.

There is probably a failed NIC (or application) in your network putting incorrect source address to the frames. Even if you are able to catch the frame you will just see the incorrect source address (you might be able to see IP address in the frame - maybe - and detect the PC via IP).

The only info you've got is the frames are coming from port 1/2. You can look to the switch connected to the other end of the line and check it's log.

If you are receiving these error messages constantly, you can try to compare the time with the syslogs on particular switches and find ports which have just come up at the time the message appeared. But this is almost impossible in a large network.




Re: Invalid traffic from multicast issue again.

These are tough , we are seeing the same message but itt says it's coming from a non existent port like 4/60 , we have kind of ignored them as they do not seem to cause a problem .

New Member

Re: Invalid traffic from multicast issue again.

This could also be some mutlicast source that use a multicast adress as source address. Usually a source will send its own address as source when it sends to destination/multicast address.