Other Switch and Layer 2 Issues

• If the units are plugged into separate switches, ensure that the switches are properly trunking and passing broad- cast/multicast traffic.
• Some switches have broadcast/multicast filtering, limiting, or “storm control” features that can break CARP.
• Some switches have broken firmware that can cause features like IGMP Snooping to interfere with CARP.
• If a switch on the back of a modem/CPE is use, try a real switch instead. These built-in switches often do not properly handle CARP traffic. Often plugging the firewalls into a proper switch and then uplinking to the CPE will eliminate problems.