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New Member

ROUTING PROBLEM

i have created 2 vlans on my 6500

vlan 10

vlan 20 (connected to vlan 30 on the 3550, no trunk)

on another 3550 switch, there are also created vlans

vlan 30 (connected to vlan 20 on the 6500, no trunk)

vlan 40

vlan 50 (connected to internet)

default routes are configured on both the switch and msfc as follows

set ip route default IP(vlan30)---switch

ip route 0.0.0.0. 0.0.0.0 IP(vlan30)---msfc

Interface SC0 is defined with IP belonging to vlan 10 and is also set to vlan 10.

routing protocol used is OSPF

OBSERVATIONS;

1. workstations on vlan 10 can communicate to vlan 20 and vise versa

2. workstations on vlan 20 can go to internet.

3. hosts on vlan 10 cannot ping vlan 30

4. hence vlan 10 cannot connect to the internet.

I am finding it hard to locate the problem.

IF ANYONE COULD HELP

7 REPLIES
VIP Purple

Re: ROUTING PROBLEM

Hello,

does your 3550 have a route to the VLAN 10 network ? Can you post both the configuration of the 3550 and the 6500 MSFC ?

Regards,

Georg

New Member

Re: ROUTING PROBLEM

3550 is running ospf...originally the 6500 is just using layer 2 wherein it is using the vlan 20 ip range.

actually i dont have any access on the 3550 yet..the vlan 30 i specified is just an assumption anyway..one thing for sure the vlan IDs on this links are different..coz am getting vlan mismatch on the interface coonected..

please bear with me as i wanted to sort out this prob asap..

thx alot

Bronze

Re: ROUTING PROBLEM

You say the 6500 is just using layer 2.

Do you mean it does not do routing between vlan 10 and 20? Or just that it is not running ospf?

In any case for this to work the 6500 will have to route between vlan 10 and 20 (or you need a trunk to the 3550 so the 3550 can route between all the vlans) and the 3550 will have to know a route to vlan 10. It can learn this via ospf (if the 6500 talks ospf) or it will need to have a static route to vlan10.

hth

Herbert

New Member

Re: ROUTING PROBLEM

that was the old scenario. Theres no vlan on the core. But now as I have mentioned, there is layer 3 implementation where i am hhaving the problem

please see my main question and scenario.

1.OSPF is running.

2.Intervlan routing is doing fine.

3.vlan directly attached to both vlan 20 and 30 is fine to all its destinations.

vlan 10 can only talk to vlan 20. cant go to the interface of vlan 30 on the 3550

another findings...i couldnt see any OSPF derived routing from the sh ip route on the msfc..

Bronze

Re: ROUTING PROBLEM

Well, the first question is if the 3550 has a route to your vlan10, but that's going to be hard to find out if you don't have access.

Anyway if you say you don't see any ospf routes on the msfc, chances are that you're not exchanging routes. Is a neighborship established, i.e. what does "sh ip os ne" show on the msfc?

New Member

Re: ROUTING PROBLEM

taking for granted they havent established neighboship , i should be able to reach at least the interface on the far switch where my core is connected, from any of my vlans coz i have intervlan routing and that is part of a subnet of 1 of my vlan..

Bronze

Re: ROUTING PROBLEM

well no:

if you ping the vlan30 interface from vlan 10, your intervlan routing will forward the echo-request packets to the 3550 and it should respond by sending echo-reply packets back to the source (the host you ping from).

The problem is that the source is a vlan10 address so the 3550 does not know where to send these reply packets to (and probably drops them, or sends them to internet)... hence your ping does not work.

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