From: Michael Dorion (dorionm@gmail.com)
Date: Mon Oct 20 2008 - 23:16:11 ARST
Oh ok, I don't think this is going to work. I thought that you had another
router or layer 3 switch to do the proxy arp. For example, if you had R3 as
a router in this VLAN and R3 had an address of 101.3.3.3 252.0.0.0, it would
think that they were both in the same subnet and then it would do local
proxy arp. Or I thought that there might be a secondary address on the third
router.
I'm not sure the exact problem but I think that the host wont reply to the
arp because the source is not reachable out the interface it was recieved
on. Weird scenerio, really makes you think.
On Mon, Oct 20, 2008 at 3:26 PM, Raheel Itrat <syedraheel@gmail.com> wrote:
> Michael
>
> There are 3 devices in total two routers connected to the same switch.( I
> mistakenly wrote BB1...there is no BB1). I have tried enabling local proxy
> arp as well....but still getting the encaps failed message... Below is the
> config
>
> R1:
> int e0
> ip local-proxy-arp
> ip address 101.1.1.1 255.255.255.0
> ip route 102.1.1.1 255.255.255.255 e0
>
> R2:
> int e0
> ip local-proxy-arp
> ip address 102.1.1.1 255.255.255.0
> ip route 101.1.1.1 255.255.255.255 e0
>
> SW1:
> int e1/1
> switch mode acc
> switch acc vlan 10
> int e1/2
> switch mode acc
> switch acc vlan 10
>
>
> On Tue, Oct 21, 2008 at 12:30 AM, Michael Dorion <dorionm@gmail.com>wrote:
>
>> The example is a little confusing without configs. Looks like you listed 4
>> device but only 2 IPs and no masks. But to do proxy-arp on the same
>> interface, the router needs to have local proxy arp enable. This is not
>> enabled by default, and you can verify with the "sho ip interface
>> <interface>" command. You should see proxy arp enabled but not local proxy
>> arp. The router would also need a route to the destination, or a wider mask.
>>
>>
>> On Mon, Oct 20, 2008 at 2:05 PM, <syedraheel@gmail.com> wrote:
>>
>>> Hi!
>>> While doing some labing I came accross an interesting scenario,,,,
>>>
>>> R1 and BB1 are connected to the same switch SW1 in same vlan 10. But the
>>> IPs of
>>> their interfaces which connect to the switch are of different subnets
>>> like
>>> 101.1.1.1 and 102.1.1.1
>>>
>>> its like R1(e0)-----(e1/1)SW1(e1/2)-----(e0)R2 , where e1/1 and e1/2 are
>>> configured in the same access vlan10
>>>
>>> Now, I cant ping between the two router interfaces, I set a static route
>>> 102.1.1.1 255.255.255.255 e0 on R1 and similarly a route back on
>>> R2.......I
>>> still see encapsulation failed on the debug.
>>>
>>> So whats happening is that when its arping for the destination address
>>> its not
>>> getting a reply back with a mac-address rite?...
>>>
>>> Can anyone explain this behaviour? How can I enable communication between
>>> the
>>> two routers?
>>>
>>> May be its too simple for a ccie forum ....but still we tend to forget
>>> the
>>> basics while studying for advance topics sometimes
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
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