# Various Nvidia specific sysctl defaults should be made in this file.
#
# arp_announce: Using 2, we will always use the best local address for this target.
# In this mode we ignore the source address in the IP packet and try to select local
# address that we prefer for talks with the target host. Such local address is selected
# by looking for primary IP addresses on all our subnets on the outgoing interface that
# include the target IP address. If no suitable local address is found we select the
# first local address we have on the outgoing interface or on all other interfaces,
# with the hope we will receive reply for our request and even sometimes no matter
# the source IP address we announce.
# By setting the arp_announce parameter to 2, we use the best local address for
# each ARP request, preferring primary addresses on the interface used to send the ARP.
# This most closely matches traditional router ARP request behavior.
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_announce = 2

# arp_ignore: With the arp_ignore parameter set to 0, if an ARP request is received
# on one interface for the IP address residing on a different interface, the switch
# will respond with an ARP reply even if the interface of the target address is down.
# This can cause a loss of traffic due to incorrect understanding about the reachability
# of next-hops, and also makes troubleshooting extremely challenging in some failure conditions.
# We set the arp_ignore value to 1 so that it will only reply to ARP requests on the interface
# which contains the target IP address. This acts much more like a traditional router and
# provides simplicity in troubleshooting and operation
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.default.arp_ignore = 1