We have two 6500 with Sup 720 and running HSRP backing up each other. BDF and IDF switches are Catalyst 3750 or 2960. Currently we are experiencing some user static hard coded their workstation ip to be one of our HSRP ip address. After workstation static assigned their IP to HSRP address, the core start log dup. IP and users start experiencing network outage. I wondering if anyone have any suggestion on how to secure their Layer 3 IP?