Using a more specific ip route

mzinz

I have a situation where my router, on one end, has a route for 10.10.0.0/16. On another interface, it needs to be sub-inted, and provide access for two more specific networks: 10.10.5.0/24, and 10.10.6.0/24.

Here's my question:
I was planning on creating three static routes, and using administrative distance, but since the router will have a sub-interface for all three of these networks, will they be considered directly connected (ie: administrative distance would be 0 for all of them).

Maybe there is no issue at all. Just trying to plan ahead. I guess that since the 10.10.5.0/24 and 10.10.6.0/24 will be on the other interface it will already have a route pointing in the right direction.

Just thinking out loud, haha

kryolla

but since the router will have a sub-interface for all three of these networks

you can't have 3 interface on all 3 of these networks it overlaps.

Rack1SW4(config-if-range)#int fa0/6
Rack1SW4(config-if)#ip add
Rack1SW4(config-if)#ip address 10.10.5.1 255.255.255.0
Rack1SW4(config-if)#int fa0/7
Rack1SW4(config-if)#ip address 10.10.6.1 255.255.255.0
Rack1SW4(config-if)#int fa0/8
Rack1SW4(config-if)#ip address 10.10.0.1 255.255.0.0
10.10.0.0 overlaps with FastEthernet0/6
Rack1SW4(config-if)#

networker050184

If I'm reading this correctly, you are saying you have 10.10.0.0/16 configured on one interface and want to put 10.10.5.0/24 and 10.10.6.0/24 on a different interface on the same router?

If that is the case its not going to work (unless you are using VRFs, which it doesn't sound like) because the addresses will be overlapping.

EDIT: You beat me to it...

kryolla

yeah I dont quite understand his question.

mzinz

Thanks for the replies guys, I'll add a bit more detail - maybe there's a simple solution.

Interface g0/0 needs to have two subinterfaces. One for 10.10.5.0/24 and one for 10.10.6.0/24.
I will also have a Tunnel interface, which is being used as the hub for a DMVPN network. There are about 60 endpoints in the DMVPN network that point back at this one router. All of these other networks are in their own 10.10.X.X. (Example: site1 is 10.10.1.0/24, site 2 is 10.10.2.0/24, etc.). There are no 10.10.5.0/24 or 10.10.6.0/24 subnets on the DMVPN network.

I realize that I could have 50 static routes, all but 2 pointing at the tunnel interface. Is there any easy way to do this? I suppose I could just put 2 static routes for 10.10.5.0 and 10.10.6.0, then let EIGRP handle the DMVPN routes...

networker050184

Still not 100% sure on what you are asking, but why not just let EIGRP carry all the routes?

mzinz

networker050184 wrote: »

Still not 100% sure on what you are asking, but why not just let EIGRP carry all the routes?

That's what I'm planning on now. Originally, I wanted to just have a single static route for all of 10.10.0.0/16, then have 2 more static routes for 10.10.5.0 and 10.10.6.0, since they were more specific.

Didn't realize you couldn't overlap like that.

Thanks again

networker050184

You can overlap routes, but not ip addresses on interfaces. If you wanted to have say 10.10.0.0/16 pointed out one interface and then 10.10.5.0/24 and 10.10.6.0/24 out another that wouldn't be an issue. The router will always route on the longest match.

mzinz

networker050184 wrote: »

You can overlap routes, but not ip addresses on interfaces. If you wanted to have say 10.10.0.0/16 pointed out one interface and then 10.10.5.0/24 and 10.10.6.0/24 out another that wouldn't be an issue. The router will always route on the longest match.

Ahhhhhhhhhhhhhh Now I see where all the confusion was.

The IP address will not overlap.

Originally (before the EIGRP talk), I was planning on doing something similar to the following (this isn't syntactically correct, obviously)

int g0/0
no ip
int g0/0.5
ip address 10.10.5.1 255.255.255.0
int g0/0.6
ip address 10.10.6.1 255.255.255.0

int t0
ip address 10.10.1.1 255.255.255.0

ip route 10.10.0.0 255.255.0.0 t0

networker050184

Yep that will work because you will have specific connected routes.