HI Netdev team,

        Greetings. We have been monitoring the vrf device approach for l3 
isolation from cumulus networks and we are currently interested in validating 
it. We have following questions on them and hoping to get answers from 
you/concerned team.

1. As per the linux documentation, there are known limits on if_index lookup, 
as the incoming if_index is changed to vrf_device index and thus an application 
receiving this packet will perceive this as a vrf_device packet, than right 
if_index. I saw you mentioned about a special flag to identify the origin, but 
didn't see the same in the latest linux 4.4.2 version code. Is there a patch 
expected for it?

2. What are the future additions planned for this approach? Are there any ipv4 
and ipv6 known bugs with vrf_device model? 

3. It has been said in the documentation that, with addition of cgroup 
functionality for vrf device, with net_admin capabilities, we should be able to 
add an interface to vrf_device, currently it is not so. Any timelines on these?

4. Currently the changes are available and portable from 4.3.x onwards. Is 
there a plan to port them to previous kernel versions? 

5. Is there a possibility of enabling secondary level lookup, to give a leak 
functionality to parent route table from device local route table? I tested 
with veth pair, configured one as default gateway, it is possible to forward 
traffic b/w the interfaces, looking for cleaner method.

6. With "VRF Device" in place,  please confirm if there are any plans to add 
VRF support for applications like 

        1.      Ping
        2.      Traceroute
        3.      DNS-Client [glibc]

        In case of DNS-Client, most of the name resolution APIs will have to 
consider the VRF to do the lookup in  and the way the domain-name/name-server 
configuration is stored.

Please revert back, if you need more clarification on the questions.

Thanks in Advance
Krishna Mohan

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