Solved: Static Route --Need input

hassan_syed6 · ‎10-04-2007

Hello,

I have a very stupid question,

Let's say i have 2 routers. Router # A and Router # B. On Router # B I have a subnet defined on Fast Ethernet 0/0 ( 10.10.10.1/24) and there are some workstations sitting behind Fas0/0 ( 10.10.10.0/24). But now on the Fas0/1 i have defined ( 10.10.10.64/26).

Now on Router # A wants to communicate with Router # B subnets, so i have a static route saying " ip route 10.10.10.0 255.255.255.0 next hop will be Router # B connection right...So for /24 Router # A will go to # B to access workstations sitting on fas0/0 ( 10.10.10.0/24)

But at the same time for network 10.10.10.64/26 sitting behind fas0/1 can i also have a static route on Router # A "ip route 10.10.10.64/26 to access with the next hop on Router # B"

My problem is with static routes one with 10.10.10.0/24 this covers the range which is defined on Fas0/1 on Router # B. Will this static route work even though /24 covers the range of /26. Wouldn't router be confused with 2 static route one specific and the other one with /24...I hope i am clear where my confusion is...

Thanks,

Hassan...

Kevin Dorrell · ‎10-04-2007

Hassan ... let's get one thing sorted out ... there is no such thing as a stupid question. Occasionally there are stupid answers tho' ;-)

About 10.10.10.0/24 and 10.10.10.64/26, one single router will not allow you to do that. It will not accept overlapping ranges on the interfaces. However, what it will allow you is 10.10.10.0/24 on F0/0 and a static route to F0/1 for 10.10.10.64/26, provided F0/1 already has another IP address on it to enable IP.

I'm not sure I understand your addresing scheme and topology well, but I think I can answer your question. A more specific route will always have priority over a less specific one. So if you have 10.10.10.0/24 going to destination X, and 10.10.10.64/26 going to destination Y, then anything in 10.10.10.64/26 will go to destination Y, and anything in the rest of 10.10.10.0/24 will go to destination X.

Is that OK?

Kevin Dorrell

Luxembourg

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Jon Marshall · ‎10-04-2007

Hassan

You shouldn't be able to configure this setup on Router B as the addressing overlaps so the router should complain when you try to address the second interface.

Jon

Kevin Dorrell · ‎10-04-2007

Hassan ... let's get one thing sorted out ... there is no such thing as a stupid question. Occasionally there are stupid answers tho' ;-)

About 10.10.10.0/24 and 10.10.10.64/26, one single router will not allow you to do that. It will not accept overlapping ranges on the interfaces. However, what it will allow you is 10.10.10.0/24 on F0/0 and a static route to F0/1 for 10.10.10.64/26, provided F0/1 already has another IP address on it to enable IP.

I'm not sure I understand your addresing scheme and topology well, but I think I can answer your question. A more specific route will always have priority over a less specific one. So if you have 10.10.10.0/24 going to destination X, and 10.10.10.64/26 going to destination Y, then anything in 10.10.10.64/26 will go to destination Y, and anything in the rest of 10.10.10.0/24 will go to destination X.

Is that OK?

Kevin Dorrell

Luxembourg

Jon Marshall · ‎10-04-2007

"Hassan ... let's get one thing sorted out ... there is no such thing as a stupid question. Occasionally there are stupid answers tho' ;-)"

Agree with Kevin on first point, no need to apologise as asking questions is how you learn.

Doubly agree with Kevin on second point about answers, just have a a look thru some of mine :)

Jon

hassan_syed6 · ‎10-04-2007

Following is what i was looking for from Kevin

""""However, what it will allow you is 10.10.10.0/24 on F0/0 and a static route to F0/1 for 10.10.10.64/26, provided F0/1 already has another IP address on it to enable IP"""

I apologies, my explanation of issue was very incorrect.

Yes Second Interface has a different range ..but on the Fas0/1 I have a Firewall sitting which will have workstations with /26 ..so 2 static route one with /24 and the other one will /26 is doable right...

Thanks,

Hassan..

Kevin Dorrell · ‎10-04-2007

Right. In that case, don't send the 10.10.10.64/26 just to F0/1, but send it to the specific IP address of the firewall on F0/1. That way the router will not have to rely on the fairwall doing proxy ARP response (which, being a firewall, it probably won't do anyway).

Kevin Dorrell

Luxembourg