Bug#892105: i40e

["Jörg Kost" <jk@ip-clear.de>]

Run into a similar issues with i40e. I found out that the i40e driver 
included in linux-image-4.9.0-6-amd64 drops ARP requests randomly if the 
interface is not configured into promiscuous mode (e.g. tcpdump 
running). Therefore if the switch / router expires or invalidates its 
arp cache, the system may not be reachable until the next ARP request 
will get randomly accepted & answered.

Workaround:
- Set up a static arp entry on the switch / router

Solution:
- Compile the current i40e driver from the Intel website, where the 
issue does not occur, in my case: 2.4.10

I did not test stretch-backports so far.