eigrp not send update

[Arie]

I have three routers, all interfaces and connections configured well, I enabled eigrp by "router eigrp 1" on all of them. On one of them i added one classfull network. The problem is when i enter debug eigrp on that router it not show any message that would proofe that it is sending updates to neighbors. Also rest routers don't get anything (routers tables checked) . What could be the reason?

[Julio E. Moisa]

Hi

Could you please provide the configuration of the routers? Have you configured no auto-summary under the EIGRP 1?

debug eigrp packet should show the communication between the EIGRP neighbors. 

[Arie]

No i did not it because of the lab, in this lab is with auto-summary (i know what it is).

Your command is showing such notifications:

R1#debug eigrp packets
EIGRP Packets debugging is on
(UPDATE, REQUEST, QUERY, REPLY, HELLO, IPXSAP, PROBE, ACK, STUB, SIAQUERY, SIAREPLY)
R1#
*Mar 1 00:13:04.335: EIGRP: Sending HELLO on FastEthernet0
*Mar 1 00:13:04.335: AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:13:07.983: EIGRP: Sending HELLO on Serial0
*Mar 1 00:13:07.983: AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:13:09.183: EIGRP: Sending HELLO on FastEthernet0
*Mar 1 00:13:09.183: AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0

but on my course i participate to CCNA my command should show send's message as well and receives (if other routers would send update - not in my case) i dont see send's so far.

This it the config of the R1 when i added my clasfull network which should be broadcasted to neighbouhrs:

R1#sh run
Building configuration...

Current configuration : 662 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname "R1"
!
!
ip subnet-zero
!
!
!
!
!
interface Ethernet0
ip address 192.168.10.5 255.255.255.252
half-duplex
no cdp enable
!
interface FastEthernet0
ip address 172.16.1.1 255.255.255.0
speed auto
no cdp enable
!
interface Serial0
ip address 172.16.3.1 255.255.255.252
clockrate 64000
no fair-queue
no cdp enable
!
interface Serial1
no ip address
shutdown
no cdp enable
!
router eigrp 1
network 172.16.0.0
auto-summary
!
ip classless
no ip http server
!
!
no cdp run
!
line con 0
line aux 0
line vty 0 4
login
!
end

R2

R2#sh run
Building configuration...

Current configuration : 736 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
resource policy
!
ip cef
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 172.16.2.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/1/0
ip address 172.16.3.2 255.255.255.252
!
interface Serial0/1/1
ip address 192.168.10.9 255.255.255.252
clock rate 64000
!
router eigrp 1
auto-summary
!
!
!
ip http server
no ip http secure-server
!
!
!
!
control-plane
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
scheduler allocate 20000 1000
end

R2#

R3

R3#sh run
Building configuration...

Current configuration : 966 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
dot11 syslog
ip source-route
!
!
!
!
ip cef
--More--
*Feb 10 23:48:33.707: %SYS-5-CONFIG_I: Configured from console no ipv6 cef
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
voice-card 0
!
!
!
!
!
archive
log config
hidekeys
!
!
!
!
!
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.10.6 255.255.255.252
duplex auto
speed auto
!
interface Serial0/3/0
no ip address
shutdown
clock rate 2000000
!
interface Serial0/3/1
ip address 192.168.10.10 255.255.255.252
!
router eigrp 1
auto-summary
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
login
!
scheduler allocate 20000 1000
end

R3#

[Julio E. Moisa]

Hi

There are not networks  configured on your EIGRP 1 on R2 and R3

[Arie]

I know. I want firstly to add subnet to R1 (the subnet 172.16.0.0) to be broadcasted but so far i don't want any subnet from either R2 and R3 to be provided. R2 and R3 should receive subnet from R1 as they have eigrp protocl activated.

[Julio E. Moisa · Accepted solution]

Well, in order to form a network using EIGRP, the IP addresses used to create the point to point between the routers must be advertised under the EIGRP process otherwise you will not receive any prefix from other routers.

[Julio E. Moisa]

For example:

I have  2 routers, R1 and R2, R1 will advertise its loopback 0 to R2

R1

interface Loopback0
ip address 1.1.1.1 255.255.255.255
!

!
interface FastEthernet0/0
bandwidth 45000
ip address 10.12.0.1 255.255.255.0
delay 10
duplex auto
speed auto
!

!
router eigrp 1
network 1.1.1.1 0.0.0.0
network 10.12.0.0 0.0.0.255
no auto-summary

R2

interface FastEthernet0/0
bandwidth 45000
ip address 10.12.0.2 255.255.255.0
delay 10
duplex auto
speed auto
!
router eigrp 1
network 10.12.0.0 0.0.0.255
no auto-summary

Then I can verify the routing table of R2:

R2#sh ip route
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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

1.0.0.0/32 is subnetted, 1 subnets
D 1.1.1.1 [90/187392] via 10.12.0.1, 00:00:18, FastEthernet0/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.12.0.0 is directly connected, FastEthernet0/0

R2#sh ip route 1.1.1.1
Routing entry for 1.1.1.1/32
Known via "eigrp 1", distance 90, metric 187392, type internal
Redistributing via eigrp 1
Last update from 10.12.0.1 on FastEthernet0/0, 00:00:25 ago
Routing Descriptor Blocks:
* 10.12.0.1, from 10.12.0.1, 00:00:25 ago, via FastEthernet0/0
Route metric is 187392, traffic share count is 1
Total delay is 5100 microseconds, minimum bandwidth is 45045 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

R2#

[Arie]

but i thought if all routers are under eigrp protocol. And at least one of them add some subnet to be broadcasted, so this subnet should be broadcasted to the others why not? Other ruters just let's say dont want to broadcast any of their subnets and that should not influence that someone wants to broadcast his subnet, they should catch it as they all implement eigrp.

Its like on below picture all routers have eigrp's enabled and only one of them says: "hey i add my subnet to be broadcasted to the others...", and others dont want to provide any of  their subnets. I think that's the way it works. I can choose what subnets i want my routers to be broadcasted (i can pick them up /or nothing)

[Julio E. Moisa]

Yes, you can say which subnets will not be advertised to the neighbors, but EIGRP must enable first an adjacency with their neighbors. 

For example on my configuration I have not advertised the loopback 0 on R2

R2

interface loopback 0
ip address 2.2.2.2 255.255.255.255 

router eigrp 1
network 10.12.0.2 0.0.0.0
no auto-summary

So R1 will not receive the prefix 2.2.2.2/32

R1

R1#sh ip route 2.2.2.2
% Network not in table
R1#
R1#
R1#sh ip route
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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

1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
10.0.0.0/24 is subnetted, 2 subnets
C 10.12.0.0 is directly connected, FastEthernet0/0

If I desire to advertise the R2's loopback 0

R2

router eigrp 1
network 2.2.2.2 0.0.0.0
network 10.12.0.2 0.0.0.0
no auto-summary

R1 will receive the prefix 2.2.2.2/32

R1#sh ip route 2.2.2.2
Routing entry for 2.2.2.2/32
Known via "eigrp 1", distance 90, metric 187392, type internal
Redistributing via eigrp 1
Last update from 10.12.0.2 on FastEthernet0/0, 00:00:43 ago
Routing Descriptor Blocks:
* 10.12.0.2, from 10.12.0.2, 00:00:43 ago, via FastEthernet0/0
Route metric is 187392, traffic share count is 1
Total delay is 5100 microseconds, minimum bandwidth is 45045 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

R1#
R1#
R1#sh ip route
Codes: C - connected, S - static, 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
i - IS-IS, su - IS-IS summary, 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

1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
D 2.2.2.2 [90/187392] via 10.12.0.2, 00:00:47, FastEthernet0/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.12.0.0 is directly connected, FastEthernet0/0

[Julio E. Moisa]

I understand but this is the way how the routing protocols like RIP, EIGRP, OSPF, ISIS, etc work. 

They need to establish an adjacency with their neighbors in  order to share the routing information. 

Now if you dont want to receive some prefixes on a router you could use filtering methods. But an adjacency must be established first.

Hope it is useful   :-)

[Arie]

So let's say we have this situation 

Router 1 have following subnets behind:

192.168.1.0 /24

192.168.2.0 /24

Router 2 have following subnets behind:

192.168.10.0

192.168.11.0

the are connected as follows:

R1  --172.168.3.1/30-------------------172.168.3.2/30  -- R2

So let's consider example:

Let's say R2 wants to broadcast only that subnet 192.168.11.0:

network 192.168.11.0

network 172.168.3.0    (as connection between R1 and R2)

and R1 doesn't want to broadcast his two subnets behind

so following your input to get the update from R2, R1 has to have at least this to be added and not inner subnets?:

network 172.168.3.0 (as this is the link between them.)

[Julio E. Moisa]

Yes exactly, R1 should create the adjacency with R2 adding the network 172.168.3.0 <subnet mask or wildcard> under the EIGRP 1 the same for R2.

R1

router eigrp 1
network 172.168.3.0 <subnet mask or wildcard>

R2

router eigrp 1
network 172.168.3.0 <subnet mask or wildcard>

Now once the adjacency is UP you will see something like:

R1(config-if)#
*Mar 1 01:03:49.535: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.12.0.2 (FastEthernet0/0) is up: new adjacency

Once the adjacency is UP you can verify that using:

show ip eigrp neighbor

R1#sh ip eigrp neighbors
IP-EIGRP neighbors for process 1
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 10.12.0.2 Fa0/0 8 00:00:30 34 204 0 18
R1#

Then you can advertise the subnet 192.168.11.0 under the EIGRP 1 on R2

[Arie]

So do i have to always to add subnet between the routers, subnets to be braodcasted.

If i would have R1, R2, R3 and if i want my updates from R1 to be broadcasted to R2 and R3 i have to add on R1 subnets between R1 ----<subnet to be added>---- R2 and R1-<subnet to be added> --->R3

What about R2 and R3 they also have to add those subnets as otherwise they will not catch update from R1?

If all above is correct, then i assume now since i got all "connection subnets (between routers)" added to eigrp so all routers knows each other, now i can choose which inner subnets from each routers add to eirgp to be boadcasted?

[Julio E. Moisa]

I dont see your topology clearly hehe but I have attached a diagram:

The adjacency should be:

R1 

router eigrp 1
network (point to point subnet between R1 and R2)
network (point to point subnet between R1 and R3)

R2 

router eigrp 1
network (point to point subnet between R1 and R2)
network (point to point subnet between R2 and R3)

R3

router eigrp 1
network (point to point subnet between R2 and R3)
network (point to point subnet between R1 and R3)

Once the EIGRP network is UP and Running you can begin to add the subnets that you want to advertise from each router.  You could remove the adjacency for example between R1 and R3.  R1 will receive the  R3's subnets via R2, That is just an example. 

[Arie]

So simply saying subnets between routers has to be added on eache ruter, othwerise will not exchange information and this has to be in place. In our case as you said even if one of them will not adjacency link beetwen other router will provide other router that info as eigrp is working, i suppose even if some of the link will be broken this will be equal to what you said if i would not add link between R1 and R3 so R2 would handle to provide R1 link to R3 and R3 about R1 am i correct with all of this i just said? Thanks.