Tshoot 300-135 (Routing IPv6 EIGRP)

Leave a Comment / By kim / 2019-07-29

Ticket #1

R1 (RID 1.1.1.1) and R2 (RID 2.2.2.2) are not forming an EIGRPv6 adjacency

Ensure that both routers form an adjacency in AS 10 using multicast.

#### Verify the problem. Check adjacency
R2#show ipv6 eigrp neighbors

#### Check if the interface has Link-Local address
R2#show ipv6 interface g1/0

#### Check the same on R1 
R1#show ipv6 interface g1/0

#### Ping test Link-local address
R1#ping FE80::2
R2#ping FE80::1

#### Check for IPv6 NE
R1#show ipv6 neighbors
R2#show ipv6 neighbors

#### Discovered there is IPv6 neighbor in STALE state

#### MAC address does not match. Incorrect static neighbor entry on R2

#### This is layer 2 problem and need to remove the manual MAC address on R2
R2#show run | i ipv6 neighbor
R2(config)#no ipv6 neighbor FE80::1 GigabitEthernet x/x feed.baba.dada

#### Verify the fix
R2#show ipv6 neighbors
R2#ping FE80::C801:BFF:FEFA:38

#### Discovered still no EIGRPv6 neighbor
R2#show ipv6 eigrp neighbors

#### Start troubleshooting Layer 3
R1#show ipv6 eigrp neighbors

#### Discovered "No usable ROuter-ID found"
R1(config)#router eigrp PS
R1(config-router)#address-family ipv6 autonomous-system 10
R1(config-router-af)#eigrp router-id 1.1.1.1

#### Still Layer 3 trouble. Investigate further
R1#show ipv6 protocols
R2#show ipv6 protocols

#### Discovered that R2's interface is in passive mode
R2#show run int gi0/1

When running EIGRP in named mode, the entire configuration is done inside the router process

#### Check on the EIGRPv6 process 10
R2#show run | sec router eigrp

#### Remove passive interface
R2(config)#router eigrp PS
R2(config-router)#address-family ipv6 autonomous-system 10
R2(config-router-af)#af-interface gi0/1
R2(config-router-af-interface)#no passive-interface

Passive-interface config is found under “address-family”

#### Check the fix
R2#show ipv6 eigrp neighbors

#### The problem is resolved but the requirement states that adjacency must be formed using multicast.

#### Check if currently using unicast
R2#show run | sec router eigrp

Currently using unicast to form adjacency

#### Remove the manual neighbor statement
R2(config)#router eigrp PS
R2(config-router)#address-family ipv6 autonomous-system 10
R2(config-router-af)#no neighbor 2001:12::1 GigabitEthernet1/0 remote 100

#### Do the same for the neighbor as currently both are using unicast
R1(config)#router eigrp PS
R1(config-router)#address-family ipv6 autonomous-system 10
R1(config-router-af)#no neighbor 2001:12::2 GigabitEthernet 1/0 remote 100

#### Verify the fix
R1#show ipv6 eigrp neighbors
R2#show ipv6 eigrp neighbors

#### R2 does not form neighbor with R1 while R1 has neighbor with R2
#### 1 way neighbor. Time for debug
R2#debug ipv6 eigrp neighbor
R2#clear logging
R2#show logging
R2#undebug all

1-way-neighbor only

#### Looks like it's access-list issue
R2#show ipv6 int gi0/1

#### Discovered there is Inbound access list "SECURE"
R2#show ipv6 access-list SECURE

#### Allow FF02:: by removing deny from the access-list
R2(config)#ipv6 access-list SECURE
R2(config-ipv6-acl)#no sequence 10

#### Verify the fix
R2#show ipv6 eigrp neighbors

Finally EIGRPv6 adjacency formed

Ticket #2

R1 and R3 aren’t forming an adjacency. Diagnose and resolve

#### Verify the problem
R3#show ipv6 eigrp neighbors

### Ping test works so no trouble on layer 1 or 2
R3#ping 2001:13::1

#### Move on to Layer 3 troubleshooting
R3#show ipv6 neighbors
R3#show ipv6 protocols

Discovered that Router mode has been shutdown

#### no shutdown
R3(config)#ipv6 router eigrp 10
R3(config-rtr)#no shutdown

#### Enable IPv6 EIGRP on the interface
R3(config)#int g1/0
R3(config-if)#ipv6 eigrp 10

#### Confirm the fix
R3#show ipv6 eigrp neighbors

#### Know the difference between EIGRP Classic vs Named modes
#### On the Named mode, all the configuration is done on the af

Ticket #3

R1, R2 and R3 do not have a route to R4’s loopback 0 address 2002::4/128

Ensure that these routers have an exact EIGRP route to this prefix and IP reachability to it.

#### Check if the closest neighbor can reach R4
R2#show ipv6 route 2002::4

#### Check topology for this prefix
R2#show ipv6 eigrp topology 2002::4/128

#### Discovered R4 is definitely not advertising its loopback to neighbors
#### Investigate the source
R4#show ipv6 eigrp topology 2002::4/128

#### Check EIGRP interfaces
R4#show ipv6 eigrp interfaces

#### Check the physical config for the loopback 0
R4#show ipv6 int br
R4#show ipv6 int brief loopback 0

#### Investigate the EIGRP config
R4#show run | sec ipv6 router

#### No shutdown interface default
R4(config-router)#router eigrp PS
R4(config-router)#address-family ipv6 autonomous-system 10
R4(config-router-af)#af-interface default
R4(config-router-af-interface)#no shutdown

#### No shutdown loopback 
R4(config-router-af)#af-interface loopback 0
R4(config-router-af-interface)#no shutdown

#### Verify the fix by checking topology table
R4#show ipv6 eigrp topology
R4#show ipv6 eigrp topology 2002::4/128

#### Verify ping reachability
R2#ping 2002::4

#### Move on to R1 to fix
#### Verify the problem
R1#show ipv6 route 2002::4

#### Check the EIGRP neighbor adjacency 
R1#show ipv6 eigrp neighbors

#### Check if there is any filter
R1#show ipv6 protocols

Discover that we have Incoming update filter with prefix-list

#### Let's take a look at the prefix-list
R1#show ipv6 prefix-list
R1#show ipv6 prefix-list INFILTER

seq 5 is blocking. Add seq 4 to permit 2002::4/128

#### Add seq 4 to permit 
R1(config)#ipv6 prefix-list INFILTER seq 4 permit 2002::4/128

#### Check the fix
R1#show ipv6 route 2002::4/128
R1#ping 2002::4

#### Fix the last router R3
#### Verify the trouble
R3#show ipv6 route 2002::4
R3#show ipv6 eigrp topology
R3#show ipv6 eigrp topology 2002::4/128
R3#show ipv6 protocols

#### Investigate more
R3#show ipv6 eigrp events
R3#show ipv6 eigrp events | i route

#### Discovered R3 has duplicated router ID 4.4.4.4
#### Check eigrp mode
R3#show run | sec ipv6 router

#### Change R3's router ID to 3.3.3.3
R3(config-rtr)#eigrp router-id 3.3.3.3

#### Check the fix
R3#show ipv6 route 2002::4
R3#ping 2002::4

Ticket #4

R1 and R4 have their loopback1 interfaces configured with the anycast IP address of 3000::14/128

R2 is learning the prefix from R4 but not R1.

Ensure that R2 learns the prefix from both R1 and R4 and performs load-sharing to the prefix.

#### Verify the trouble
R2#show ipv6 route 3000::14
R2#show ipv6 eigrp topology 3000::14/128

#### Check if here is any distribute-list
R2#show ipv6 protocols
R2#show ipv6 protocols | begin EIGRP

#### Check the source if it is advertising
R1#show ipv6 eigrp topology 3000::14/128

#### Check if there is any Outbound distribute-list 
R1#show ipv6 protocols
R1#show ipv6 protocols | b EIGRP

#### Discovered no issue on the source router.
#### Go back to neighbor R2 for further troubleshooting
R2#show ipv6 eigrp events
R2#show ipv6 eigrp events | i 3000::14
R2#show ipv6 eigrp events | i Ignore

Discovered that R2 has duplicated RID (same as R1)

#### Fix duplicated RID (Check current config)
R2#show run | sec router
R2#show run | sec ipv6 eigrp

#### Change RID
R2(config)#router eigrp PS
R2(config-router)#address-family ipv6 autonomous-system 10
R2(config-router-af)#no eigrp router-id 1.1.1.1
R2(config-router-af)#eigrp router-id 2.2.2.2

#### Verify fix
R2#ping 3000::14
R2#show ipv6 route 3000::14
R2#traceroute 3000::14

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