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New Member

ios 15 on 3925 does not learn all arp updates at checkpoint firewall cluster failover like ios 12 on 7206vxr does. Any ideas?

We try to replace two 7206VXR Internet uplink Routers running IOS-12 (c7200-is-mz.123-6e.bin) by two 3925 Routers running IOS-15 .


The problem we are facing is that ios 15 on 3925 does not learn/update all arp updates (i.e. about 5 out of 200 public NAT-IPs are not updated correctly) at checkpoint firewall cluster failover (which also happens at every config-updates where it switches to the standby unit and then back to the primary immediately) like ios 12 on 7206vxr does.


Latest 15.1 , 15.2 and 15.3 releases already tried -> same behavior.

Increasing the global arp queue to 8192 (from 512 which is the ios-15 Default) also did not help.

Also Updating to the latest Checkpoint Version R77.10 did not help.

The Checkpoint VMAC-Feature is currently used as a workaround, but the situation still occurs as soon as one checkpoint cluster node is disabled (which disables also the VMAC-Feature and tries to update the router's arp tables with the only active node's MAC-address for all NAT-IPs).


Interestingly we could not reproduce the problem running the checkpoint Cluster nodes in Virtual Machines. So this is maybe related to gratuitous arps for the 200 NAT-IPs being sent out too fast.


Does anyone have similar experiences or ideas how to follow up?

  • LAN Switching and Routing
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New Member

We have experienced the same

We have experienced the same issue with CP firewall Active Standby with L2 network to Internet router.

Most of NAT were done on CP and experience the same issue on code 15.4.

Partial Arp get updated and most of them did not which cause outage on some web service application.

CP also uses static MAC with PCAP during failover we can confirm the G ARP did broadcast but no sign on router giving back ARP request for the result.

There are roughly ~100 NATed IP behind CP and half of them remain the same in arp cache after failover.

Ticket was opened for the case and I wish we could have the answer in 3 years time. 

netcrafteng , Did your case

netcrafteng , Did your case was resolved ?