Configuring VRRP 1059What Is VRRP Accept Mode?The accept mode allows the switch to respond to pings (ICMP EchoRequests) sent to the VRRP virtual IP address. The VRRP specification (RFC3768) indicates that a router may accept IP packets sent to the virtual routerIP address only if the router is the address owner. In practice, this restrictionmakes it more difficult to troubleshoot network connectivity problems. Whena host cannot communicate, it is common to ping the host's default gatewayto determine whether the problem is in the first hop of the path to thedestination. When the default gateway is a virtual router that does notrespond to pings, this troubleshooting technique is unavailable. In thePowerConnect switch VRRP feature, you can enable Accept Mode to allowthe system to respond to pings that are sent to the virtual IP address.This capability adds support for responding to pings, but does not allow theVRRP master to accept other types of packets. The VRRP master responds toboth fragmented and un-fragmented ICMP Echo Request packets. TheVRRP master responds to Echo Requests sent to the virtual router's primaryaddress or any of its secondary addresses.Members of the virtual router who are in backup state discard ping packetsdestined to VRRP addresses, just as they discard any Ethernet frame sent to aVRRP MAC address.When the VRRP master responds with an Echo Reply, the source IPv4address is the VRRP address and source MAC address is the virtual router'sMAC address.What Are VRRP Route and Interface Tracking?The VRRP Route/Interface Tracking feature extends VRRP capability to allowtracking of specific routes and interface IP states within the router that canalter the priority level of a virtual router for a VRRP group.VRRP interface tracking monitors a specific interface IP state within therouter. Depending on the state of the tracked interface, the feature can alterthe VRRP priority level of a virtual router for a VRRP group.NOTE: An exception to the priority level change is that if the VRRP group is the IPaddress owner, its priority is fixed at 255 and cannot be reduced through thetracking process.
