EIGRP basic config

 interface serial 0
   ip add 192.168.1.1 255.255.255.0
   ip add 133.6.81.3 255.255.255.0 secondary
   ip hello-interval eigrp 64 10
   ip hold-time eigrp 64 30
   bandwidth 64
   ip bandwidth-percent eigrp 50
   ip summary-address eigrp 64 192.168.10.0 255.255.240.0 120
 !
 router eigrp 64
   passive-interface FastEthernet0/0
   network 10.1.1.0 0.0.63.255
   network 172.17.5.0 0.0.0.255
   no auto-summary

• Always set the bandwidth for serials, to adjust metric: change the DELAY in 10ms, so that it will not to affect other protocols [OSPF].
• Send summary address to RIP/IGRP with the correct network mask.
• EIGRP Summary address is done at interface that advertises out in EIGRP instead of at the AS in OSPF.
• Cannot do summary-routes on discontiguous networks ==> blackhole.
• AN INTERFACE MUST EXIST THAT COVERS THE SUMMARY ADDRESS.
• EIGRP will not auto-summarize external routes unless there is a component of the same major network that is a route that is interneal to EIGRP.
• External EIGRP routes have an administrative distance of 170, and should use the default metric.
• The passive-interface command prevents the exchange of EIGRP routes on the interface.
• EIGRP will still include the address of the interface in routing updates sent out to the other non-passive interfaces.
• EIGRP summarizes the route only when advertising out an interface that is in a different class.