eigrp crookbook eigrp 02...

add another router...

add to eigrp 1

r2

router eigrp 1
netw 172.16.1.0 0.0.0.255

r3

router eigrp 1
netw 172.16.1.0 0.0.0.255
netw 3.0.0.0

r3(config-router)#
*Sep 30 07:23:29: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.16.1.2 (FastEthernet0/0) is up: new adjacency

r1#sh ip route eigrp

Gateway of last resort is not set

      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/2297856] via 10.1.1.2, 00:24:40, Serial2/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/2300416] via 10.1.1.2, 00:01:03, Serial2/0
      172.16.0.0/24 is subnetted, 1 subnets
D        172.16.1.0 [90/2172416] via 10.1.1.2, 00:01:45, Serial2/0

filter r3's loopback...

r2(config)#access-list 1 deny 3.3.3.0
r2(config)#access-list 1 permit any
r2(config)#router eigrp 1
r2(config-router)#distribute-list 1 in f0/0

this filters the loopback incoming to r2, and permits the rest...

r1#sh ip route eigrp

Gateway of last resort is not set

      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/2297856] via 10.1.1.2, 00:27:55, Serial2/0
      172.16.0.0/24 is subnetted, 1 subnets
D        172.16.1.0 [90/2172416] via 10.1.1.2, 00:05:00, Serial2/0

r3#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 1 subnets
D        1.1.1.0 [90/2300416] via 172.16.1.2, 00:06:58, FastEthernet0/0
      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/156160] via 172.16.1.2, 00:06:58, FastEthernet0/0
      10.0.0.0/24 is subnetted, 1 subnets
D        10.1.1.0 [90/2172416] via 172.16.1.2, 00:06:58, FastEthernet0/0

you can do the same outgoing from r2 to r3... we'll drop the advertisement to r3 of r1's loopback...

r2(config)#access-list 2 deny 1.1.1.0
r2(config)#access-list 2 permit any
r2(config)#router eigrp 1
r2(config-router)#distribute-list 2 out f0/0

r3#sh ip route eigrp

Gateway of last resort is not set

      2.0.0.0/24 is subnetted, 1 subnets
D        2.2.2.0 [90/156160] via 172.16.1.2, 00:11:05, FastEthernet0/0
      10.0.0.0/24 is subnetted, 1 subnets
D        10.1.1.0 [90/2172416] via 172.16.1.2, 00:11:05, FastEthernet0/0

r2#sh ip proto
*** IP Routing is NSF aware ***

Routing Protocol is "eigrp 1"
  Outgoing update filter list for all interfaces is not set
    FastEthernet0/0 filtered by 2 (per-user), default is not set
  Incoming update filter list for all interfaces is not set
    FastEthernet0/0 filtered by 1 (per-user), default is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP-IPv4 Protocol for AS(1)
    Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
    NSF-aware route hold timer is 240
    Router-ID: 2.2.2.2
    Topology : 0 (base)
      Active Timer: 3 min
      Distance: internal 90 external 170
      Maximum path: 4
      Maximum hopcount 100
      Maximum metric variance 1

  Automatic Summarization: disabled
  Maximum path: 4
  Routing for Networks:
    2.0.0.0
    10.0.0.0
    172.16.1.0/24
  Routing Information Sources:
    Gateway         Distance      Last Update
    10.1.1.1              90      00:09:00
    172.16.1.3            90      00:03:39
  Distance: internal 90 external 170

prefix lists are mostly used to filter eigrp with bgp and the converse... we'll get to that later...