RIP Class C Routes
Brownie1985
Member Posts: 34 ■■□□□□□□□□
in CCNA & CCENT
Hi Guys, was hoping someone to help with a quick question
Would anyone be able to explain to myself why when using RIP with a no auto-summary a class c networks of say 192.168.0.0, 192.168.1.0, 192.168.2.0 are just listed as one route of
R 192.168.0.0/24 is up, routing via 10.10.10.1, FastEthernet0/0
Just to help explain, say you have three routers (2 interfaces each) plugged into a switch with each interface in the switch given an address of 10.10.0.0/24, then the other interfaces again plugged into its own switch with the interfaces having 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24. With this setup the routes do no probigate to the other routes. But if I changes the 192.168.0.0 ranges to class B 172.16.0.0/24, 172.16.1.0/24, 172.16.2.0/24 the routes will propigate.
Is this due to the 192.168.0.0 address already being classed as a class C so the route that would be advertised when you enter command network 192.168.0.0 would be [192.168.0].0 with the last ].0 being the variable it would be looking to be different on the subnet?
Hope my ramble kinda makes sense for the question I am asking.
Thanks
Would anyone be able to explain to myself why when using RIP with a no auto-summary a class c networks of say 192.168.0.0, 192.168.1.0, 192.168.2.0 are just listed as one route of
R 192.168.0.0/24 is up, routing via 10.10.10.1, FastEthernet0/0
Just to help explain, say you have three routers (2 interfaces each) plugged into a switch with each interface in the switch given an address of 10.10.0.0/24, then the other interfaces again plugged into its own switch with the interfaces having 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24. With this setup the routes do no probigate to the other routes. But if I changes the 192.168.0.0 ranges to class B 172.16.0.0/24, 172.16.1.0/24, 172.16.2.0/24 the routes will propigate.
Is this due to the 192.168.0.0 address already being classed as a class C so the route that would be advertised when you enter command network 192.168.0.0 would be [192.168.0].0 with the last ].0 being the variable it would be looking to be different on the subnet?
Hope my ramble kinda makes sense for the question I am asking.
Thanks
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Comments
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Eildor Member Posts: 444Brownie1985 wrote: »Hi Guys, was hoping someone to help with a quick question
Would anyone be able to explain to myself why when using RIP with a no auto-summary a class c networks of say 192.168.0.0, 192.168.1.0, 192.168.2.0 are just listed as one route of
R 192.168.0.0/24 is up, routing via 10.10.10.1, FastEthernet0/0
Just to help explain, say you have three routers (2 interfaces each) plugged into a switch with each interface in the switch given an address of 10.10.0.0/24, then the other interfaces again plugged into its own switch with the interfaces having 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24. With this setup the routes do no probigate to the other routes. But if I changes the 192.168.0.0 ranges to class B 172.16.0.0/24, 172.16.1.0/24, 172.16.2.0/24 the routes will propigate.
Is this due to the 192.168.0.0 address already being classed as a class C so the route that would be advertised when you enter command network 192.168.0.0 would be [192.168.0].0 with the last ].0 being the variable it would be looking to be different on the subnet?
Hope my ramble kinda makes sense for the question I am asking.
Thanks
Are you running RIP version 2? What networks are listed when you do a "show ip protocols"? -
Brownie1985 Member Posts: 34 ■■□□□□□□□□Version 2 is running on all routers with no auto-summary, just checked to make sure. Its odd as this all works fine when using a class b address subnetted to /24 - here is a quick output since changing back to 192.168.0.0 ranges
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.10.0 is directly connected, FastEthernet0/0
R 10.10.20.0 [120/1] via 10.10.10.3, 00:00:20, FastEthernet0/0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
R 172.16.0.0/16 is possibly down, routing via 10.10.10.3, FastEthernet0/0
R 172.16.2.0/24 is possibly down, routing via 10.10.10.2, FastEthernet0/0
R 172.16.3.0/24 is possibly down, routing via 10.10.10.3, FastEthernet0/0
C 192.168.0.0/24 is directly connected, FastEthernet0/1
You can see it was picking up the router correctly when using 172.16.0.0 addresses and all the routers are using network 192.168.0.0. This is only something I have done in GNS, but cant get my head around why using class c address when workNext Targets:
70-294
CCENT -
Eildor Member Posts: 444Brownie1985 wrote: »Version 2 is running on all routers with no auto-summary, just checked to make sure. Its odd as this all works fine when using a class b address subnetted to /24 - here is a quick output since changing back to 192.168.0.0 ranges
10.0.0.0/24 is subnetted, 2 subnets
C 10.10.10.0 is directly connected, FastEthernet0/0
R 10.10.20.0 [120/1] via 10.10.10.3, 00:00:20, FastEthernet0/0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
R 172.16.0.0/16 is possibly down, routing via 10.10.10.3, FastEthernet0/0
R 172.16.2.0/24 is possibly down, routing via 10.10.10.2, FastEthernet0/0
R 172.16.3.0/24 is possibly down, routing via 10.10.10.3, FastEthernet0/0
C 192.168.0.0/24 is directly connected, FastEthernet0/1
You can see it was picking up the router correctly when using 172.16.0.0 addresses and all the routers are using network 192.168.0.0. This is only something I have done in GNS, but cant get my head around why using class c address when work
What happens if you were to disconnect the directly connected 192.168.0.0/24 network?
Is there a way for you to send me the GNS3 file? -
Monkerz Member Posts: 842What network commands are you using under each rip process?
"network 172.16.0.0" would advertise 172.16.0.0, 172.16.1.0 and 172.16.2.0, but "network 192.168.0.0" would only advertise 192.168.0.0.
I think this is what you were asking in your first post. -
Eildor Member Posts: 444Monkerz is right -- did you include network statements for each of the networks (192.168.x.0)?
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Brownie1985 Member Posts: 34 ■■□□□□□□□□What network commands are you using under each rip process?
"network 172.16.0.0" would advertise 172.16.0.0, 172.16.1.0 and 172.16.2.0, but "network 192.168.0.0" would only advertise 192.168.0.0.
I think this is what you were asking in your first post.
YESSS!!! Thats it, just quickly wizzed this up. I was looking at a completely different angle as how the classful network command works!
All makes sense now, as the 172.16.0.0 class B network has .16 as the last net mask, so other bits are expected to change, where as 192.168.0.0 class c expects that the .0 will stay the same as it's netmask goes to 192.168.0.
Thank you very much, can't believe I didn't see this. All the routes are as should be expectedNext Targets:
70-294
CCENT