BCM50 Critical Error - Duplicate IP address detected on startup of LAN

[barrywebb]

I have a long installed BCM50 system and have just received the following error:

Priority: <critical>
Message: eventID=60005; message=LAN Driver - Duplicate IP address detected on startup of LAN interface.; problemResolution=Check in diagnostics logs for messages log for futher information. Also Check your network to ensure no other devices are using the same IP address as the system.

Component: NCGL
Host: bcmm50r3
Process: [1319]:

I have looked through the logs but can find no additional information.

The BCM50 is connected to a router and a single expansion installed with a 4x16 combo (NT5B42AAABE5). The BCM has a static IP.

Any help would be very welcome!

 

[QueBall780]

You have a duplicate IP address or some kind of loop in your LAN.

Fix it.

Try unplugging the BCM50 and do a ping on the IP address, Getting a response indicates you for sure have another device on the network with that IP address.

Check the ARP table on your machine after doing the ping even if you do not get a response. If you see a MAC address for that IP you have a device on the network using that IP.

Verify you have not cross connected your switches causing a loop in the network. (Unless all your network switches specifically support these kinds of loops for redundancy purposes)

Use a protocol sniffer on the line and watch the packets being sent and received by the BCM50 when it gets plugged in to see the source of the duplicate IP address warning.

Those warnings do not occur for no reason, you have an issue on your network.

 

[barrywebb]

Thanks for the reply QueBall780.

This network consists of the router (at 192.168.1.1 static), the BCM50 (at 192.168.1.50 static)and a PC (192.168.1.100 dynamic). So I'm at a loss to understand where the conflict could be. I assume that the BCM50 communicates with the expansion chassis on a separate internal network.

I was hoping that the error log would provide some more detail i.e. which IP address was in conflict but I can only find reference to the error in the alarms.systemlog and it's pretty short on detail and I can't find any reference to the error in any of the othere logs.

I will look at the arp table as you suggest to see if that throws any light on the problem.

Thanks again for your help.

 

[curlycord]

Also check the routers IP range, I see your PC is 100, this would almost mean your BCM then should be 1XX and not XX.
In other words your Router starts handing out IP starting at 100 and up and not below.

You could simply change it to 150 and see if works.




=----(((((((((()----=
curlycord

http://www.curlycord.com

 

[barrywebb]

Hi Curlycord, thanks for the input.

The router allocates dynamic IPs in the range 100 - 199. I gave the BCM50 a static address below that range (192.168.1.50) to avoid possible conflict.

I'm planning on working on the system later today and will report what I find.

My biggest issue is the lack of detail in the BCM50's logs that would have helped me isolate the problem. After all, if it detected an IP address conflict, it has knowledge of same (the IP address at least). Providing that information would have made resolving this problem significantly easier.

Thanks again.

 

[curlycord]

I get it now.

arp -a

Maybe do above command with and without BCM on network.





=----(((((((((()----=
curlycord

http://www.curlycord.com

 

[barrywebb]

Problem solved!

Someone had added a printer to the network and given it the same IP address as the BCM50. My mistake for not checking but I assumed (stupid, I know) that a duplicate IP address should not have occurred.

Thanks for the excellent advice. The moral of the story is of course, assume nothing.