EIGRP usually uses a multicast to IP address 224.0.0.10 for its messages.There is an option to configure it to use a unicast address with the command neighbor ip-address .

R(config)# router eigrp < as_no >
R(config-router)# neighbor <ip-address> <interface>

Verification:

R# debug ip packet

Lab:
EIGRP Unicast