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Full Version: Cisco Routing: "ip default-network" vs. Default Static Routes
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A single point of confusion for some CCNA and CCNP candidates is the difference in between configuring a static default route and utilizing the Cisco routing command ip default-network.

At 1st glance, they appear to do the same thing. Each configure a location to which packets should be routed if there is no a lot more certain route in the routing table.

The key difference amongst these two options is that configuring a static default route only defines a default route for the router you're configuring it on, whilst ip default-network will propagate the route via its routing protocol.

Let's examine the routing tables of a hub-and-spoke network employing the ip default-network command. Be taught more on our affiliated website - Click here: understandable. The Future Of Creative Advertising: Looki... | Diigo includes further concerning where to consider it. R1 is the hub and R2 and R3 are the spokes. They are directly connected by means of the network 172.12.123. /24, and each and every has a loopback with a 32-bit mask that are numbered according to the router number (1.1.1.1, etc.) RIP is operating on all 3 routers and the loopbacks are advertised.

R1 has one more serial interface with the IP address ten.1.1.1 /24, and this network has been flagged as a default network with the command ip default-network ten... . It is not getting advertised by RIP.

The routing protocol will then promote this route. With RIP, the default network is advertised as ... . (With IGRP, it appears as the network quantity, but is marked as an IGRP External route. ) This route has been designated a candidate default route on R1, as we see with the asterisk subsequent to the ten... /24 network (code table removed for brevity):

R1#show ip route

Gateway of final resort is not set

1.../32 is subnetted, 1 subnets

C 1.1.1.1 is straight connected, Loopback0

R two.../eight [120/1] via 172.12.123.2, 00:00:11, Serial0

R 3.../eight [120/1] by way of 172.12.123.3, 00:00:11, Serial0

172.12../16 is variably subnetted, two subnets, two masks

C 172.12.21./30 is directly connected, BRI0

C 172.12.123./24 is directly connected, Serial0

* ten.../24 is subnetted, 1 subnets

C ten.1.1. is straight connected, Serial1

On R2 and R3, a default RIP route is now seen (code tables once again deleted):

R2#show ip route

Gateway of final resort is 172.12.123.1 to network ...

R 1.../8 [120/1] by means of 172.12.123.1, 00:00:00, Serial0.213

2.../32 is subnetted, 1 subnets

C two.2.2.2 is directly connected, Loopback0

R three.../eight [120/2] through 172.12.123.1, 00:00:00, Serial0.213

172.12../16 is variably subnetted, 2 subnets, two masks

C 172.12.21./30 is straight connected, BRI0

C 172.12.123./24 is directly connected, Serial0.213

R* .../ [120/1] by means of 172.12.123.1, 00:00:00, Serial0.213

R3#show ip route

Gateway of final resort is 172.12.123.1 to network ...

R 1.../8 [120/1] via 172.12.123.1, 00:00:27, Serial0.31

R two.../8 [120/two] through 172.12.123.1, 00:00:28, Serial0.31

3.../32 is subnetted, 1 subnets

C three.3.3.three is straight connected, Loopback0

172.12../24 is subnetted, 1 subnets

C 172.12.123. If you have an opinion about police, you will likely want to research about IAMSport. For different viewpoints, please consider looking at: go there. is directly connected, Serial0.31

R* .../ [120/1] by means of 172.12.123.1, 00:00:28, Serial0.31

And the default route performs, considering that we can ping 10.1.1.1 from both R2 and R3. Since they have no other match in their routing tables, they use the default route.

R2#ping 10.1.1.1

Sort escape sequence to abort.

Sending 5, one hundred-byte ICMP Echos to 10.1.1.1, timeout is two seconds:

!!!!!

Good results rate is 100 % (5/five), round-trip min/avg/max = 68/68/68 ms

R3#ping 10.1.1.1

Kind escape sequence to abort.

Sending 5, one hundred-byte ICMP Echos to ten.1.1.1, timeout is two seconds:

!!!!!

Accomplishment rate is 100 % (five/5), round-trip min/avg/max = 68/68/68 ms

When deciding whether to use a default static route or a default network, hold in thoughts that if you want the routing protocol to propagate the default route, the ip default-network command will do that for you. But if you want only the nearby router to have the default route, a static IP route is the way to go..
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