Configuring Default route in RIP

Configuring Default route in RIP:

  ·         There are 3 ways to advertise a default route in RIP

   1.  Default-information originate

2.  Ip default-network

3.  Redistribute static default route

·         Let me take a small topology to configure default route in RIP

 

R1------S1/0-------------s1/0----R2----s1/1--------------s1/1------R3

10.1.12.1--------------10.1.12.2-----10.1.13.2--------------10.1.13.3

·         Let me configure all these options in R2, so that it will generate default route towards R1

 

R1#show run | sec router

router rip

 version 2

 passive-interface default

 network 10.0.0.0

 neighbor 10.1.12.2

 no auto-summary

R1#

 

R2(config)#do show run | sec router

router rip

 version 2

 passive-interface default

 network 10.0.0.0

 neighbor 10.1.12.1

 no auto-summary

R2(config)#

 

R1#show 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

 

     10.0.0.0/24 is subnetted, 2 subnets

R       10.1.13.0 [120/1] via 10.1.12.2, 00:00:20, Serial1/0

C       10.1.12.0 is directly connected, Serial1/0

R1#

 

R2(config)#do show 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

 

     10.0.0.0/24 is subnetted, 2 subnets

C       10.1.13.0 is directly connected, Serial1/1

C       10.1.12.0 is directly connected, Serial1/0

R2(config)#

 

Observations:

·         RIP is configured between R1 and R2.

·         No default route or static router is configured in R1 or in R2

 

1.  Let me configure default-information originate option:

 

R2(config)#router rip

R2(config-router)#default-information originate

R2(config-router)#

 

R1#show 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 10.1.12.2 to network 0.0.0.0

 

     10.0.0.0/24 is subnetted, 2 subnets

R       10.1.13.0 [120/1] via 10.1.12.2, 00:00:00, Serial1/0

C       10.1.12.0 is directly connected, Serial1/0

R*   0.0.0.0/0 [120/1] via 10.1.12.2, 00:00:00, Serial1/0

R1#

 

Observation:

·         R1 has received default-route from R2

 

2.  Let me configure redistribute static option now:

 

R2(config)#router rip

R2(config-router)#no default-information originate

R2(config-router)#exit

R2(config)#ip route 0.0.0.0 0.0.0.0 ser1/1

R2(config-router)#redistribute static metric 2

R2(config-router)#

 

R2(config-router)#do show 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 0.0.0.0 to network 0.0.0.0

 

     10.0.0.0/24 is subnetted, 2 subnets

C       10.1.13.0 is directly connected, Serial1/1

C       10.1.12.0 is directly connected, Serial1/0

S*   0.0.0.0/0 is directly connected, Serial1/1

R2(config-router)#

 

R1#show 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 10.1.12.2 to network 0.0.0.0

 

     10.0.0.0/24 is subnetted, 2 subnets

R       10.1.13.0 [120/1] via 10.1.12.2, 00:00:07, Serial1/0

C       10.1.12.0 is directly connected, Serial1/0

R*   0.0.0.0/0 [120/2] via 10.1.12.2, 00:00:07, Serial1/0

R1#

 

Observation:

·         R1 has received default-route from R2

 

3.  Let me configure ip default-network option now:

 

R2(config)#router rip

R2(config-router)#no redistribute static metric 2

R2(config-router)#no ip route 0.0.0.0 0.0.0.0 ser1/1

R2(config)#ip default-network 10.0.0.0

R2(config)#

 

R2(config)#do show 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

 

 *   10.0.0.0/24 is subnetted, 2 subnets

C       10.1.13.0 is directly connected, Serial1/1

C       10.1.12.0 is directly connected, Serial1/0

R2(config)#

 

R1#show 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 10.1.12.2 to network 0.0.0.0

 

     10.0.0.0/24 is subnetted, 2 subnets

R       10.1.13.0 [120/1] via 10.1.12.2, 00:00:11, Serial1/0

C       10.1.12.0 is directly connected, Serial1/0

R*   0.0.0.0/0 [120/1] via 10.1.12.2, 00:00:11, Serial1/0

R1#

Observation:

·         R1 has received default-route from R2