routing issue 10.0.0.0

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Jan 11th, 2009
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Hello all. I am having a routing issue with a cisco 1812. To explain the situation we have x4 cisco 1812's all connected via VPN to another cisco 1812. the central cisco 1812 has two WAN connections too different ISP's. 2 vpn's are connected on 1 WAN interface, and 2 vpn's are connected on the other. All vpns are up. there is a single vlan with a route back to all of our 10.0.0.0/8 numbers which doesn't work. When this route is changed to something more specific on our network such as 10.160.0.0/16 routing works.


So can anyone tell me how to get 10.0.0.0 routing ? or tell me why it isn't routing the entire A class.


Please keep in mind we have 5 of these other routers in other parts of the world routing 10.0.0.0 numbers back out through our MPLS, but this one using dual WAN's on different isp's doesn't seem to want to route the entire 10.0.0.0/8 range.


just for some general info. each of the 4 routers are split up into 4 subnets. 10.199.5.0/26. and the central router is on a 10.199.4.0/24 subnet.

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Richard Burts Mon, 01/12/2009 - 05:28
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Nathan


One of the things that can cause the symptoms that you describe is if the router is configured with no ip classless. This used to be the default in IOS (many releases ago) but now the default is ip classless. Can you check and see if the router is configured with ip classless or with no ip classless?


To test it out, I would suggest that you enter the command ip classless in global configuration and see if it helps with your problem.


HTH


Rick

nathan.carroll@... Mon, 01/12/2009 - 14:58
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Thankyou for your input rbuts,


Besides just re-typing to command, is there any other way that i can see if ip classless is enabled or disabled ?


But yes i tried that command with no luck. Would you like me to post any specific outputs ?


interface Vlan1

description #- MPLS

ip address 10.199.4.220 255.255.255.0

!

interface Vlan2

description #- Internal

ip address 10.199.32.1 255.255.248.0

!

ip forward-protocol nd

ip route 0.0.0.0 0.0.0.0 211.x.x.135

ip route 0.0.0.0 0.0.0.0 126.x.x.154

ip route 10.0.0.0 255.0.0.0 10.199.4.2

ip route 192.168.0.0 255.255.0.0 10.199.4.2


They are the routes that are in use at the moment. the 3rd route down for 10.0.0.0 is the one that is not working but needs to be to route all of our traffic out through the mpls.


Would it work to use a dynamic routing protocol ? Any suggestions are always helpful :)

Richard Burts Tue, 01/13/2009 - 09:10
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Nathan


I am not aware of a good way to see whether is it ip classless or no ip classless other than to look through the config or to enter the command again.


I am puzzled why it is not routing for other parts of 10.0.0.0. Perhaps it would help if you would post the output of show ip route.


Depending on your environment a dynammic routing protocol might work very well.


HTH


Rick

nathan.carroll@... Tue, 01/13/2009 - 13:37
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We will be putting the router back in place tomorrow to do some extra testing so i will get a show IP route then. Our next plan is to route 10.0.0.0/9 and 10.128.0.0/10, which will route everything up to 10.192.0.0. This is working on the theory that the 10.199.0.0 on the local subnet is causing some kind of issue. (maybe cause there is already a route for 10.199.0.0 for the local subnet and 10.0.0.0 over laps it). Not that that should matter, but we are getting thin on ideas.

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