This article is all about redistribution configuration lab between two eigrp autonomous system . Here in this lab we will configure EIGRP having different autonomous number. To show Multiple EIGRP AS configuration on same router i am using cisco packet tracer. You can see EIGRP neighbors with different AS numbers in this lab and you will learn how to configure it to communicate them.In below topology diagram you can see EIGRP Topology having different Autonomous Value. There are total three routers R1, R2 and R3 R1 is in As 1 while R3 in AS 2. But R2 is in both AS.Now read carefully how i am going to configure it.
Step 1:Assign IP Address on Router R1:
Router>enable Router#config t Router(config)#host R1 R1(config)#int fa0/1 R1(config-if)#ip add 1.0.0.1 255.0.0.0 R1(config-if)#no shut R1(config-if)#exit R1(config)#int fa0/0 R1(config-if)#ip add 2.0.0.1 255.0.0.0 R1(config-if)#no shut
Step 2:Assign IP Address on Router R2:
Router>enable Router#config t Router(config)#host r2 r2(config)#host R2 R2(config)#int fa0/0 R2(config-if)#ip add 2.0.0.2 255.0.0.0 R2(config-if)#no shut R2(config-if)#exit R2(config)#int fa0/1 R2(config-if)#ip add 3.0.0.1 255.0.0.0 R2(config-if)#no shut
Step 3:Assign IP Address on Router R3:
Router>enable Router#config t R3(config)#int fa0/0 R3(config-if)#ip add 3.0.0.2 255.0.0.0 R3(config-if)#no shut R3(config-if)#exit R3(config)#int fa0/1 R3(config-if)#ip add 4.0.0.1 255.0.0.0 R3(config-if)#no shut
Step 4:EIGRP configuration on Router R1:
R1(config)#router eigrp 1 R1(config-router)#network 1.0.0.0 R1(config-router)#network 2.0.0.0 R1(config-router)#exit
Step 5:EIGRP configuration on Router R2:
R2(config)#router eigrp 1 R2(config-router)#network 2.0.0.0 R2(config-router)#exit R2(config)#router eigrp 2 R2(config-router)#network 3.0.0.0 R2(config-router)#exit
Step 6: EIGRP configuration on Router R3:
R3(config)#router eigrp 2 R3(config-router)#network 3.0.0.0 R3(config-router)#network 4.0.0.0
Step 7:Redistribute EIGRP Autonomous system 1 in to EIGRP Autonomous System 2
R2(config)#router eigrp 1 R2(config-router)#redistribute eigrp 2 R2(config-router)#exit
Step 8:Redistribute EIGRP Autonomous system 2 in to EIGRP Autonomous System 1
R2(config)#router eigrp 2 R2(config-router)#redistribute eigrp 1 R2(config-router)#exit R2(config)#do write Building configuration... [OK] R2(config)#
Step 10: EIGRP Verification and Troubleshooting
I am on PC0 and now I am going to check IP address of PC0 using ipconfig command.
PC>ipconfig FastEthernet0 Connection:(default port) Link-local IPv6 Address.........: FE80::230:F2FF:FEC1:5B11 IP Address......................: 1.0.0.2 Subnet Mask.....................: 255.0.0.0 Default Gateway.................: 1.0.0.1
Now Test network communication using ping command.
PC>ping 4.0.0.2 Pinging 4.0.0.2 with 32 bytes of data: Reply from 4.0.0.2: bytes=32 time=0ms TTL=125 Reply from 4.0.0.2: bytes=32 time=0ms TTL=125 Reply from 4.0.0.2: bytes=32 time=0ms TTL=125 Reply from 4.0.0.2: bytes=32 time=1ms TTL=125 Ping statistics for 4.0.0.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 1ms, Average = 0ms PC>
Step 11:Check and Verify EIGRP Traffic
Step 12:Check and Verify EIGRP Topology
Step 13:Check and Verify EIGRP Neighbors
Step 14:Check and verify EIGRP INTERFACES having Different AS(Autonomous System)
R2#show ip eigrp interfaces IP-EIGRP interfaces for process 1 Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes Fa0/0 1 0/0 1236 0/10 0 0 IP-EIGRP interfaces for process 2 Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes Fa0/1 1 0/0 1236 0/10 0 0 R2#
Step 15:Check and Verify Routing Protocol
R2#show ip protocols Routing Protocol is "eigrp 1 " Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0 EIGRP maximum hopcount 100 EIGRP maximum metric variance 1 Redistributing: eigrp 1, Automatic network summarization is in effect Automatic address summarization: Maximum path: 4 Routing for Networks: 2.0.0.0 Routing Information Sources: Gateway Distance Last Update 2.0.0.1 90 1282082 Distance: internal 90 external 170 Routing Protocol is "eigrp 2 " Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0 EIGRP maximum hopcount 100 EIGRP maximum metric variance 1 Redistributing: eigrp 2, Automatic network summarization is in effect Automatic address summarization: Maximum path: 4 Routing for Networks: 3.0.0.0 Routing Information Sources: Gateway Distance Last Update 3.0.0.2 90 1358909 Distance: internal 90 external 170
Step 16: Check and Verify EIGRP Routing Tables
R2#show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set D 1.0.0.0/8 [90/30720] via 2.0.0.1, 00:04:08, FastEthernet0/0 C 2.0.0.0/8 is directly connected, FastEthernet0/0 C 3.0.0.0/8 is directly connected, FastEthernet0/1 D 4.0.0.0/8 [90/30720] via 3.0.0.2, 00:02:36, FastEthernet0/1
Learn Linux CCNA CEH IPv6 Cyber-Security Online 
For two way Redistribution, you actually need to set tagging on your redistribute statements, otherwise “Route leaking” can occur where Routes are shared back across the network that are already known.
An example of such a Route-Map:
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#route-map EIGRP2OSPF permit 10 <—– Sequence # 10 in Route-Map
R1(config-route-map)#set tag 100
R1(config-route-map)#exit
R1(config)#route-map OSPF2EIGRP deny 10 <—– Sequence # 10 in Route-Map
R1(config-route-map)#match tag 100
R1(config-route-map)#route-map OSPF2EIGRP permit 20
The actual Route-Map itself:
R1#sh route-map
route-map EIGRP2OSPF, permit, sequence 10
Match clauses:
Set clauses:
tag 100
Policy routing matches: 0 packets, 0 bytes
route-map OSPF2EIGRP, deny, sequence 10
Match clauses:
tag 100
Set clauses:
Policy routing matches: 0 packets, 0 bytes
route-map OSPF2EIGRP, permit, sequence 20
Match clauses:
Set clauses:
Policy routing matches: 0 packets, 0 bytes
R1#
So R1 EIGRP routes going into the OSPF Domain are tagged as 100, and OSPF routes going into the EIGRP Domain are going to Deny any routes tagged as 100, and allow the rest through.
The bottom Route-Map Sequence # 20 is a "Catch All" Clause saying "All other traffic route normally" and has no tagging / actions configured to be taken.
Just to be clear about Route Redistribution, unless you are doing it one way, tagging / route-maps or a similar mechanism for tagging routes must be used 🙂
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