Member since December 02, 2012
1 stage of confusion for some CCNA and CCNP candidates is the variance amongst configuring a static default route and utilizing the Cisco routing command ip default-network.
At initially look, they seem to do the same issue. Equally configure a vacation destination to which packets ought to be routed if there is no much more particular route in the routing table.
The significant variation among these two choices is that configuring a static default route only defines a default route for the router you are configuring it on, even though ip default-network will propagate the route by means of its routing protocol.
Let us take a look at the routing tables of a hub-and-spoke network making use of the ip default-network command. R1 is the hub and R2 and R3 are the spokes. They are right linked by way of the network 172.twelve.123. /24, and every has a loopback with a 32-bit mask that are numbered in accordance to the router number (1.one.one.1, etc.) RIP is running on all a few routers and the loopbacks are marketed.
R1 has another serial interface with the IP tackle 10 binary options trading online .1.one.1 /24, and this network has been flagged as a default network with the command ip default-network 10... . It is not getting marketed by RIP.
The routing protocol will then market this route. With RIP, the default network is advertised as ... . (With IGRP, it seems as the network number, but is marked as an IGRP Exterior route. ) This route has been designated a applicant default route on R1, as we see with the asterisk up coming to the 10... /24 network (code table eliminated for brevity)
R1show ip route
Gateway of very last resort is not set
1.../32 is subnetted, one subnets
Do one.one.one.1 is immediately related, Loopback0
R two.../eight 120/1 by means of 172.12.123.two, 000011, Serial0
R three.../8 120/1 by means of 188.8.131.52, 000011, Serial0
172.twelve../sixteen is variably subnetted, two subnets, 2 masks
Do 172.12.21./thirty is directly linked, BRI0
Do 172.twelve.123./24 is directly related, Serial0
* 10.../24 is subnetted, one subnets
Do 10.1.1 binary options trading systems . is straight linked, Serial1
On R2 and R3, a default RIP route is now noticed (code tables yet again deleted)
R2show ip route
Gateway of previous resort is 172.12.123.one to network ...
R 1.../8 one hundred twenty/1 through 184.108.40.206, 000000, Serial0.213
two.../32 is subnetted, one subnets
C two.two.2.two is immediately linked, Loopback0
R 3.../eight 120/2 through 172.twelve.123.one, 000000, Serial0.213
172.12../16 is variably subnetted, two subnets, 2 masks
Do 172.12.21./30 is specifically connected, BRI0
Do 172.twelve.123./24 is specifically related, Serial0.213
R* .../ one hundred twenty/1 via 172.twelve.123.1, 000000, Serial0.213
R3show ip route
Gateway of very last resort is 172.12.123.one to network ...
R one.../eight one hundred twenty/1 by means of 172.12.123.one, 000027, Serial0.31
R two.../8 a hundred and twenty/2 by means of 220.127.116.11, 000028, Serial0.31
three.../32 is subnetted, 1 subnets
C three.3.three.3 is directly connected, Loopback0
172.12../24 is subnetted, one subnets
C 172.12.123. is specifically linked, Serial0.31
R* .../ one hundred twenty/1 binary options by way of 172.twelve.123.one, 000028, Serial0.31
And the default route will work, due to the fact we can ping 10.one.1.1 from equally R2 and R3. Since they have no other match in their routing tables, they use the default route.
Sort escape sequence to abort.
Sending 5, 100-byte ICMP Echos to ten.1.one.one, timeout is 2 seconds
Accomplishment rate is a hundred % (five/5), spherical-trip min/avg/max 68/68/68 ms
Form escape sequence to abort.
Sending five, one hundred-byte ICMP Echos to ten.1.1.1, timeout is 2 seconds
Accomplishment rate is 100 p.c (five/5), spherical-excursion min/avg/max 68/68/68 ms
When selecting whether to use a default static route or a default network, maintain 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 neighborhood router to have the default route, a static IP route is the way to go.