KEY CONCEPTS:

An EIGRP router(s) from which the STUB RECEIVE-ONLY is enabled will ONLY RECEIVED the network advertise by other neighbor EIGRP router(s) but it will NOT advertised.

In my topology above, I will be enabling STUB RECEIVE-ONLY on the MELBOURNE ROUTER.

MANILA#sh run | sec eigrp
router eigrp 12
network 100.100.100.0 0.0.0.255
 network 192.168.12.0

MELBOURNE#sh run | section eigrp
router eigrp 12
 network 192.168.12.0
 network 192.168.23.0
 network 200.200.200.0

SINGAPORE#sh run | sec eigrp
router eigrp 12
 network 150.150.150.0 0.0.0.255
 network 192.168.23.0

Now, I will be enabling EIGRP STUB RECEIVE-ONLY on MELBOURNE and let’s see the output of the Routing Table of the three routers.

MELBOURNE#config t
Enter configuration commands, one per line.  End with CNTL/Z.
MELBOURNE(config)#router eigrp 12
MELBOURNE(config-router)#eigrp stub receive-only
MELBOURNE(config-router)#

Let’s have a look into the Routing Table

MELBOURNE#sh ip route eigrp
Codes: L – local, 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, H – NHRP, l – LISP
       + – replicated route, % – next hop override

Gateway of last resort is not set

      100.0.0.0/24 is subnetted, 1 subnets
D        100.100.100.0 [90/2297856] via 192.168.12.1, 00:00:18, Serial2/0
      150.150.0.0/24 is subnetted, 1 subnets
D        150.150.150.0 [90/2297856] via 192.168.23.3, 00:00:17, Serial2/1

>> As observed, MELBOURNE ROUTER have received two network address from MANILA and SINGAPORE which is their respective Loopback address.
Let’s see what happens to the routing table of MANILA Router.

MANILA#sh ip route  eigrp
Codes: L – local, 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, H – NHRP, l – LISP
       + – replicated route, % – next hop override

Gateway of last resort is not set

MANILA#


>>> As observed above, it shows that NO ROUTES were advertised by MELBOURNE ROUTER.

Let’s see what does the SINGAPORE Routing Table shows up.

SINGAPORE#show ip route eigrp
Codes: L – local, 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, H – NHRP, l – LISP
       + – replicated route, % – next hop override

Gateway of last resort is not set

SINGAPORE#

>> Similarly, the MELBOURNE Router did not share the etwork address that it receives from MANILA ROUTER.