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(usagi-users 04061) Re: ping6 is sent out from wrong interface

Hi Naohiro,

>Hi Marcus
>Thank you for your quick reply.
>> It's due to routing.
>For the reason of selecting 'eth0', I agree.
>But, I think the device is specified before looking up the 
>routing table in this case.

Well, ping's man page reads: 
       -I interface address
              Set source address to specified interface  address.  Argument
              may  be  numeric  IP  address or name of device. When pinging
              IPv6 link-local address this option is required.

So you only set the address, not the interface to be used for sending.

>> ...with eth0 being preferred over eth1 for multicast packets.
>> You could add a dedicated route for ff02::/16 to make the 
>kernel output the packet via eth1.
>This works when using only "eth1" for multicasts.
>When multiple I/Fs are connected to separate networks, this 
>scheme requires changing the route every time a user need to 
>send ping to different network.

Ok, my proposition was a bit too general. It would probably be better to set up routes for the exact addresses. So in your case to ff02::1. 

Of course, if you wish to send the same packet via several interfaces within a short time, this would still result in adding and deleting the routes over and over again.

>I think kernel can solve this problem better.

I don't think this would be intended....


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