gives some assurance that traffic is actually flowing to and from one
or more peers on the local network.
-The ARP monitor relies on the device driver itself to verify
-that traffic is flowing. In particular, the driver must keep up to
-date the last receive time, dev->last_rx. Drivers that use NETIF_F_LLTX
-flag must also update netdev_queue->trans_start. If they do not, then the
-ARP monitor will immediately fail any slaves using that driver, and
-those slaves will stay down. If networking monitoring (tcpdump, etc)
-shows the ARP requests and replies on the network, then it may be that
-your device driver is not updating last_rx and trans_start.
-
7.2 Configuring Multiple ARP Targets
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