EIGRP CONFIGURATION

EIGRP (ENHANCED INTERIOR GATEWAY ROUTING PROTOCOL)
EIGRP Basics - A number of powerful features make EIGRP a real standout from IGRP and other protocols. The main ones are listed here:
Support for IP and IPv6 (and some other useless routed protocols) via protocol-dependent modules
Considered classless (same as RIPv2 and OSPF)
Support for VLSM/CIDR
Support for summaries and discontiguous networks
Efficient neighbor discovery
Communication via Reliable Transport Protocol (RTP)
Best path selection via Diffusing Update Algorithm (DUAL)

EIGRP CONFIGURATION
Router# config t
Router(config)# router eigrp 20 Here 20 Indicates autonomous system
Router(config-router)# network 172.16.0.0
Router(config-router)# network 10.0.0.0
R3(config-router)#no autosummary Turns off the auto-summarization feature.

Command passive-interface - Configuring in EIGRP prevents the interface from participating in the routing process by preventing the sending and receiving of hello packets.
Router(config)# router eigrp 20
Router(config-router)# passive-interface serial 0/1

Setting Maximum Paths and Hop Count - EIGRP has a maximum hop count of 100 but can be set up to 255. Chances are you wouldn’t want to ever change this, but if you did, here is how you would do it:
Router(config)# router eigrp 10
Router(config-router)# maximum-paths ? <1-6> Number of paths

Router(config)#router eigrp 10
Router(config-router)# metric maximum-hops ? <1-255> Hop count