We have a PIX 525 in a failover environment. We have another appliance called a Packetshaper model 7500 that we are attempting to install. This appliance is a QOS/bandwidth prioritization appliance. What is happening is our firewall interfaces have proxy ARP enabled. The engineer from Packetshaper indicated that what is happening is the PIX is responding to ARP requests on various interfaces which in turn is interfering with the management capabilities of the Packetshaper. I do not want to turn any of this off before getting some expert opinion from someone as to what ramifications turning this off may have. We are running in a NAT environment with ACL’s on the firewall. Since it seems that proxy ARP can be removed from particular interfaces, I would imagine that we are looking to turn this off (if possible) on our inside and dmz1 interfaces. These are the networks where this appliance will be visible through. I have emailed Cisco as well however I wanted to see if anyone had any idea about this.