H3C A5500 : ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict

[ferdo]

Hi

I got the following error message on my router H3C A5500.

%May 17 23:38:44:272 2015 PLC_RO_BOUCLE CFGMAN/5/CFGMAN_CFGCHANGED: -EventIndex=549-CommandSource=2-ConfigSource=3-ConfigDestination=2; Configuration is changed.

%May 18 11:42:02:064 2015 PLC_RO_BOUCLE ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict. The device with MAC address 0008-5d1c-67cc connected to Bridge-Aggregation1 in VLAN 130 and the device with MAC address 0008-5d1c-6763 connected to Bridge-Aggregation1 in VLAN 130 are using the same IP address 10.6.130.20.

%May 18 11:42:15:560 2015 PLC_RO_BOUCLE ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict. The device with MAC address 0008-5d1d-4c19 connected to Bridge-Aggregation1 in VLAN 130 and the device with MAC address 0008-5d1d-4add connected to Bridge-Aggregation1 in VLAN 130 are using the same IP address 10.6.130.14.

And as this problem is not quickly resolved, all my network has been blocked for a day. The network has once again become operational when I isolated the site whence the IP address conflict is detected.
Could someone tell me why the A5500 blocks all my network because of a single IP address conflict detected ?
Thank you a lot

Ferdo

[Thej0sepH]

Hello,

You get duplicated IP for 2 reasons:

1. Real duplicated IP, you should follow the port Bridge-Aggregation 1 and check where is the duplicated IP, the device brand should be '00-08-5D' : AASTRA. However i don't think this is the case, because a duplicated IP causes problems with the device duplicated, not with the network.
2. Loops in the network, you are receiving the same packets from diferent ports, so your switch thinks that are different devices with the same IP.

It seems to be a loop problem or maibe a bad LACP configured. Have you configured LACP recently? Can you show us display lacp brief command.

Do you have spanning tree activated on your network? If not, you should activate it on all switches. Spanning Tree is a standard protocol so you should be able to implement it between different brands (check the same spanning tree version is on every switch, different versions can cause loops also)

You can also try disconecting ports looking for the loop, make a continuous ping and start disconnecting ports until you find the loop.

What site did you isolated to recover your network?

Greetings

Luis

[ferdo]

Hi  Luis

Hello Luis
Thank you very much for your reply.
I have not seen a message indicating a loop in the network. I attached the A5500 log and config files. The problem began on May 18 at 11 am 42 and ended the same day at 6 pm 18 - when I isolated my sites where the router reported IP address conflicts. 
The only link aggregation configured on this router connects this A5500 to my core network. And that day no more server connected to the core network does not respond to ping. No loop message on my core network either.
I also attach the config A5500 also.

Tell me what other commands I should add for the spanning tree please.

Regards

Ferdo

[metnet]

Hi,

in my case i just ignore these messages because i noticed them everyday and they're related to my checkpoint cluster. Each firewall share the virtual IP address and i see it from different interfaces but there is no issue in my network.

Bye

Fabio