Administrative Distance Vs Longest Prefix Match

please setup your lab similar to previous lab

add this line to R2


router eigrp 1
 passive-interface Serial0/0
 network 10.1.1.0 0.0.0.255
 network 172.16.2.0 0.0.0.3
 no auto-summary

ip route 192.168.0.0 255.255.0.0 172.16.2.1

now R2 have two routes to reach 192.168.1.1

via EIGRP with AD = 90

via static route with AD = 1

R2#sh ip route

...

D    192.168.1.0/24 [90/2323456] via 10.1.1.1, 00:05:57, FastEthernet0/0

S    192.168.0.0/16 [1/0] via 172.16.2.1

guess.. which path will the router use to reach 192.168.1.1 ? some of you may though that it'll be static because it has AD = 1, let's test..

R2#traceroute 192.168.1.1

..

  1 10.1.1.1 4 msec 4 msec 4 msec

  2 172.16.1.1 12 msec 12 msec * 

unfortunately it choose to use route learn via EIGRP.. thru R3. This is because it prefer longest prefix match compare to AD

destination : 192.168.1.1

EIGRP route = 192.168.1.0/24

Static route = 192.168.0.0/16

EIGRP has the longest match..