The standby firewall does not take over when the primary firewall fails. The "%PIX-4-405001: Received ARP response collision from IP address/mac address of device with duplicate IP address> on interface" log message is displayed

[TCC_2]

Core issue

This issue occurs when a duplicate IP address matching one of the active firewall's IP addresses is  present on the same network subnet as the firewalls when the active firewall fails.

This issue is documented in Cisco bug ID CSCsc34022.

Resolution

Be careful while defining the IP addressing scheme in the network. Make sure that there is no duplicate IP address already used as one of the interface IP addresses used in the network (either on the primary or secondary firewall).

For a workaround, upgrade the software to version 7.0 (5) or later.