Proxy ARP and Gratuitous ARP on VIPs
-
All -
I am getting over a rather long day that was made so by a Cisco ASA active/standby failover pair and a sudden change of outside MAC address (which should have been anticipated by me).
The Cisco ASA does not send gratuitous ARP for static NAT addresses. So everything looked great. Could ping to the ISP, could ping everything inside, good NAT translations, but none of the connections going in or out on the other addresses in the /26 would work.
The Metro-E provider's ARP cache timeout is 4 hours. Ugh.
A thorough ass-chewing - at best - is expected in the morning.
But that brings me to pfSense. Will one of the VIP types result in gratuitous ARP being transmitted in such a case? We're talking on a reboot, disconnect/reconnect of WAN, etc? Note that the ASA would have proxy ARPed just fine. Trouble is that would only happen after the <= 4 hour expiration of the provider's ARP entry and them generating an ARP request.
OMFG 4 hours is a long time. DO NOT let your outside MAC address change unless you are already on the phone with someone who can clear the ARP on the other side. Ugh. Virtual active/standby MAC addresses for the MFing win.
