Duplicate IP address between Node1 and Node2 in HA Pair

[#1]

Hi All,

Do you have an experience with this:

So I already set the grid master and wanna configure a new member as a HA pair and check the Enable port redundancy on LAN1/LAN2 & use LAN1 when available. and the IP address configurations are:

MGMT IP node1: 10.246.128.3

MGMT IP node2: 10.246.128.4

VIP               : 10.254.4.175

HA node1     : 10.254.4.187

HA node2     : 10.254.4.188

LAN1 node1 : 10.254.4.166

LAN1 node2 : 10.254.4.167

everything is working normally with LAN1 node2 as an active node.

LAN1 node1 -> passive

LAN1 node2 -> active

the problem is when I try to test the HA failover with "force HA failover", LAN1 node2 becames passive node and LAN1 node1 was shown offline in grid master's GUI but I can reach the LAN1 node1 by ping and SSH.

When I "show interface" in MGMT node1, it has error "ERROR: Duplicate IP address:10.254.4.166! Check lan interface".

to solved the offline member, I waived the node1 and rejoin. It works but in SSH show interface, the error still show.

I suspect this problem show because enabling the port redundancy on LAN1/LAN2 & use LAN1 when available and I think it will be a problem in the next day if the HA pair switch role/failover.

Do you all have an experience like this? and how to solved the duplication?

Thank you

Best Regards.

Rio

[#2 · Accepted solution]

The duplicate IP warning is thrown when another device responds to an ARP broadcast from the appliance. When using port redundancy, this works in an active/passive relationship whereby LAN2 is only used if LAN1 is down. If you are seeing this warning, most likely there is another device on the network which is using that IP.

To test this out and resolve the issue, try the following:

1. Take the appliance which is reporting the duplicate IP offline (shut it down, disable both of its network interfaces at the switch, or unplug both network cables).
2. Review the CAM tables for the subnet and identify what MAC addresses are using that IP.
3. Trace the MAC addresses to a specific switch port and correct the offending host.

Alternatively, change the LAN1 IP address to a known free IP address. This should also help resolve the issue.

Regards,

Tony

[#3]

Hi Tony,

Thank you for your response.

So its sure because there is an other device use the same IP, not because of LAN1 & LAN2 right?

the user in investigate the network if there is other user/device using same IP.

Thank you.

Best Regards,

Rio