Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Invalid CRC


I'm receiving the next message on a Catalyst 4006:

%SYS-4-P2_WARN: 1/Invalid crc, dropped packet, count = 292839

Somebody knows what can be the source of this message, or where can I check the possible cause?

Thanks in advanced!

Cisco Employee

Re: Invalid CRC

What software version are you running? I suggest that you upgrade to either 5.5(18) or 6.3(10) and if you still see the issue, open a TAC case. It could be a bad Supervisor if you see them in the latest CAT OS. Also if it is due to a bad Supervisor engine, the sup engine might fail POST test. So back up your configs before you reset/upgrade

Re: Invalid CRC


This is from the "Error Decoder"

1. %SYS-4-P2_WARN: Host [mac addr] is flapping between port [dec/dec] and port [dec/dec]

The above message indicates that your Catalyst 4000 switch has learned a MAC address that already exists in its CAM table on a port other than the original one.

Recommended Action: What you need to do is to track down how this MAC address was learned from both ports.

Step 1: Consider port the first port. Issue the show cam dynamic [port] command. If you see the MAC address 00:50:0f:20:08:00 coming out in the list of the MAC addresses learned on this port, try to see if this is a single host that is connected or if there are multiple hosts registered on that port.

Step 2: If it is a single host that is connected, check the other port that is registered and see if the host is dually attached to the switch. If however, the host has connections to other devices that can eventually lead back into this switch, try to track down the intermediate devices that are in between.

Note: The best way to achieve this (assuming that they are Cisco devices) is to use the output of the command show cdp neighbors detail.

2. %SYS-4-P2_WARN: Filtering Ethernet MAC address of value zero

The "Filtering Ethernet MAC address of value zero" syslog message is generated when the switch receives packets with a source MAC address of 00-00-00-00-00-00, which is an invalid source MAC.

Recommended Action: The syslog message indicates that the switch is refusing to learn the invalid address. However, the switch will forward traffic sourced from an all zeros MAC address. Try to identify the end station that is generating frames with an all 0's source MAC address. Typically, such frames are transmitted from a traffic generator (for example, SmartBits), certain types of servers (such as load balancing IBM WebSphere servers), a misconfigured router or end station (for example, a device transmitting all 0's broadcasts), or a faulty NIC.

Maybe this helps you.



CreatePlease login to create content