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Community Member

invalid multicast address

Hi.

I receive the following message at least 10 times a day:

"2003 Mar 12 06:42:14 %SYS-4-P2_WARN: 1/Invalid traffic from multicast source address 45:00:00:6c:1e:b5 on port 2/1"

The address always begins with: 45:00:00 and the last 3 pairs change.

I am trying to find who is sending this invalid multicast messages.

port 2/1-2/2 & 3/1-3/2 are in giga etherchannel on cat 6509 connecting to cat 4006.

The other messages arrives from all ports in the giga etherchannel.

Any idea???

Thanks,

Danny.

2 REPLIES

Re: invalid multicast address

Here is the description for the error message from the Cisco documentation:

%SYS-4-P2_WARN: 1/Invalid traffic from multicast source address

Problem: The switch is generating Invalid traffic from multicast source address messages.

Description: The following is an example of the syslog output you will see when this error occurs:

SYS-4-P2_WARN: 1/Invalid traffic from multicast

source address 81:00:01:00:00:00 on port 2/1

%SYS-4-P2_WARN: 1/Invalid traffic from multicast

source address 81:00:01:01:00:00 on port 2/1

The Invalid traffic from multicast source address syslog message is generated when the switch receives packets with a multicast MAC address as the source MAC. Using a broadcast or multicast MAC address as the source MAC for a frame is not standards-compliant behavior. However, the switch still forwards traffic sourced from a multicast MAC address.

The syslog message indicates the multicast MAC address in the source MAC field of the frame, and the port on which the traffic was received.

The workaround is to try to identify the end station that is generating frames with a multicast source MAC address. Typically, such frames are transmitted from a traffic generator (for example, SmartBits) or third party devices that share a multicast MAC address (for example, load balancing firewall or server products).

Community Member

Re: invalid multicast address

since it comes from a giga etherchannel port and not from a port connected to a edge switch I can't find the source of the station/switch that send the message.

still looking for an idea to solve the problem.

thanks.

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