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EIGRPCCNA 200-301

EIGRP Redistribution from OSPF Not Appearing

Presenting Symptom

Routes redistributed from OSPF into EIGRP are not appearing in the EIGRP topology table or routing table of other EIGRP routers.

Network Context

A small branch office with two routers: R1 (AS 100) runs EIGRP on its LAN interfaces and OSPF on a WAN link to the corporate network. R1 is configured to redistribute OSPF routes into EIGRP. R2, an EIGRP neighbor, should receive these redistributed routes but does not. IOS version 15.x, typical enterprise branch setup.

Diagnostic Steps

1

Check EIGRP topology table on R2

show ip eigrp topology
P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

IP-EIGRP Topology Table for AS(100)/ID(10.1.1.2)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

P 10.0.0.0/8, 1 successors, FD is 28160
        via 10.1.1.1 (28160/2560), Serial0/0
P 192.168.1.0/24, 1 successors, FD is 30720
        via 10.1.1.1 (30720/2816), Serial0/0

If the redistributed OSPF routes (e.g., 172.16.0.0/16) are missing from the topology table, the redistribution is not working. If they appear but are not in the routing table, check administrative distance or next-hop reachability.

2

Verify redistribution configuration on R1

show running-config | section router eigrp
router eigrp 100
 network 10.1.1.0 0.0.0.255
 redistribute ospf 1 metric 10000 100 255 1 1500

Check that the redistribute command is present and includes a metric. If missing metric, EIGRP will not accept redistributed routes. Also verify OSPF process ID matches.

3

Check OSPF database on R1 to confirm routes exist

show ip ospf database
OSPF Router with ID (10.1.1.1) (Process ID 1)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
10.1.1.1        10.1.1.1        120         0x80000002 0x00A0B1 1
10.2.2.2        10.2.2.2        110         0x80000001 0x00C0D2 1

                Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
10.1.1.2        10.1.1.2        100         0x80000001 0x00E0F3

                Summary Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
172.16.0.0      10.2.2.2        90          0x80000001 0x00A1B2

If the OSPF database does not contain the expected routes (e.g., 172.16.0.0), the problem is upstream OSPF, not redistribution. If routes are present, redistribution should work.

4

Check EIGRP redistribution statistics

show ip eigrp traffic
IP-EIGRP Traffic Statistics for AS 100
  Hellos sent/received: 100/100
  Updates sent/received: 10/10
  Queries sent/received: 0/0
  Replies sent/received: 0/0
  Acks sent/received: 5/5
  Input queue high water mark: 1
  Input queue depth: 0
  Output queue high water mark: 1
  Output queue depth: 0
  Redistribution: 0 routes redistributed

If 'Redistribution: 0 routes redistributed' appears, the redistribute command is not being applied. Check for typos or missing metric. If non-zero, routes are being redistributed but possibly filtered or not advertised.

Root Cause

The redistribute ospf 1 command under router eigrp 100 is missing the required metric values (bandwidth, delay, reliability, load, MTU). EIGRP will not accept redistributed routes without a metric specified either in the redistribute command or via a default-metric command.

Resolution

On R1, configure the redistribute command with proper metric or set a default-metric. Option 1: Add metric to redistribute command: R1(config)# router eigrp 100 R1(config-router)# redistribute ospf 1 metric 10000 100 255 1 1500 Option 2: Set default-metric: R1(config)# router eigrp 100 R1(config-router)# default-metric 10000 100 255 1 1500 R1(config-router)# redistribute ospf 1 The metric values: bandwidth (Kbps), delay (tens of microseconds), reliability (0-255), load (0-255), MTU (bytes).

Verification

On R2, run 'show ip eigrp topology' and 'show ip route eigrp'. Expected output should now include the redistributed OSPF routes, e.g., show ip route eigrp D EX 172.16.0.0/16 [170/30720] via 10.1.1.1, 00:00:05, Serial0/0 Also verify on R1: 'show ip eigrp traffic' should show non-zero redistribution count.

Prevention

1. Always specify a metric when configuring redistribution, either in the redistribute command or via default-metric. 2. Use route-maps to control which routes are redistributed and to set metrics conditionally. 3. Test redistribution in a lab before deploying to production.

CCNA Exam Relevance

On the CCNA 200-301 exam, redistribution questions often appear in troubleshooting scenarios where a missing metric causes routes not to be redistributed. Expect multiple-choice or drag-and-drop questions asking to identify the missing configuration. Key fact: EIGRP requires a metric for redistributed routes; without it, the routes are not injected into EIGRP.

Exam Tips

1.

Remember that EIGRP redistribution requires a metric; without it, the redistribute command is ignored.

2.

The metric order for EIGRP is bandwidth, delay, reliability, load, MTU (bandwidth in Kbps, delay in tens of microseconds).

3.

Use 'show ip eigrp traffic' to quickly see if redistribution is occurring (look for 'Redistribution: X routes redistributed').

Commands Used in This Scenario

show ip eigrp topology

Displays the EIGRP topology table, showing all learned routes and their feasible successors, used to verify EIGRP convergence and path selection.

show ip eigrp traffic

Displays EIGRP packet statistics including sent/received counts for each packet type, used to verify EIGRP neighbor communication and troubleshoot packet loss or authentication issues.

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