How to Configure Default Route to the Routers


Here we are going to see how to configure default route in a routers ,we can configure default route for stub network. i.e dead end router we can point an ip address  or exit interface for all packets that came to that router.Here we go..

Steps:

Steps 1:Her e, in our topology we have two stub network .




Apply basic configurations ip address to all interfaces and pc's



Step 2:Configure static route on R2 to route packets for 10.0.0.0 and 40.0.0.0 networks like this


R2(config)#ip route Destination Network| Destination N/W SubnetMask |Next Hop Address or Exit Interface

In Router R2

R2(config)#ip route 10.0.0.0 255.0.0.0 20.0.0.1
R2(config)#ip route 40.0.0.0 255.0.0.0 30.0.0.2





Step 3:Now we are going to configure default route on R1 and R3.So the routers forward packets to assigned ip address next hop address or exit interface



In Router R1

R1(config)#ip route 0.0.0.0 0.0.0.0 20.0.0.2


In Router R3

R3(config)#ip route 0.0.0.0 0.0.0.0 30.0.0.1


Here, 0.0.0.0 0.0.0.0 represents any network any subnetmask. i.e any packet that came to router R1 will be forwarded to next hop address 20.0.0.2.Now check the routing table of R1


R1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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 20.0.0.2 to network 0.0.0.0

C    10.0.0.0/8 is directly connected, FastEthernet0/0
C    20.0.0.0/8 is directly connected, Serial2/0
S*   0.0.0.0/0 [1/0] via 20.0.0.2
               is directly connected, Serial2/0




S* represents Static default route .Now Ping from 10.0.0.10 to 40.0.0.10 you will get reply as


PC>ping 40.0.0.10

Pinging 40.0.0.10 with 32 bytes of data:

Reply from 40.0.0.10: bytes=32 time=141ms TTL=125
Reply from 40.0.0.10: bytes=32 time=187ms TTL=125
Reply from 40.0.0.10: bytes=32 time=172ms TTL=125
Reply from 40.0.0.10: bytes=32 time=125ms TTL=125

Ping statistics for 40.0.0.10:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 125ms, Maximum = 187ms, Average = 156ms




we can also configure exit interface instead of next hop address like this 



R1(config)#ip route 0.0.0.0 0.0.0.0 serial 2/0

R3(config)#ip route 0.0.0.0 0.0.0.0 serial 3/0




Administrative distance if configure with next hop address is 1,for exit interface is 0....



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