A layer 3 network device (220, 300), comprising: one or more processors to: identify (110, 410) one or more first interfaces (A, B) used by the layer 3 network device to communicate with one or more other network devices, the layer 3 network device using one or more second interfaces to communicate with one or more multicast receiver devices that are different from the one or more other network devices; store information that identifies the one or more first interfaces used to communicate with the one or more other network devices, wherein store information comprises: store a routing flag in association with an interface identifier stored in a multicast outgoing interface list, the routing flag indicating that an interface, identified by the interface identifier and included in the one or more first interfaces, is used to communicate with another network device, of the one or more other network devices, rather than with a multicast receiver device of the one or more multicast receiver devices; receive a packet; determine (130, 430) that the packet includes a bidirectional forwarding detection message, associated with a bidirectional forwarding detection protocol, to be used to verify multicast connectivity with a multicast source device; identify the one or more first interfaces based on the stored information and based on determining that the packet includes the bidirectional forwarding detection message; and transmit (140, 450) the packet via the one or more first interfaces without transmitting the packet via the one or more second interfaces. identify (110, 410) one or more first interfaces (A, B) used by the layer 3 network device to communicate with one or more other network devices, the layer 3 network device using one or more second interfaces to communicate with one or more multicast receiver devices that are different from the one or more other network devices; store information that identifies the one or more first interfaces used to communicate with the one or more other network devices, wherein store information comprises: store a routing flag in association with an interface identifier stored in a multicast outgoing interface list, the routing flag indicating that an interface, identified by the interface identifier and included in the one or more first interfaces, is used to communicate with another network device, of the one or more other network devices, rather than with a multicast receiver device of the one or more multicast receiver devices; receive a packet; the layer 3 network device using one or more second interfaces to communicate with one or more multicast receiver devices that are different from the one or more other network devices; store information that identifies the one or more first interfaces used to communicate with the one or more other network devices, wherein store information comprises: store a routing flag in association with an interface identifier stored in a multicast outgoing interface list, the routing flag indicating that an interface, identified by the interface identifier and included in the one or more first interfaces, is used to communicate with another network device, of the one or more other network devices, rather than with a multicast receiver device of the one or more multicast receiver devices; receive a packet; determine (130, 430) that the packet includes a bidirectional forwarding detection message, associated with a bidirectional forwarding detection protocol, to be used to verify multicast connectivity with a multicast source device; identify the one or more first interfaces based on the stored information and based on determining that the packet includes the bidirectional forwarding detection message; and transmit (140, 450) the packet via the one or more first interfaces without transmitting the packet via the one or more second interfaces.