Avoiding ARP flux on the multi-interface Linux hosts

Avoiding ARP flux on the multi-interface Linux hosts

A Linux host with two or more Ethernet interfaces on the same subnet may cause the Address Resolution Protocol (ARP) flux issue when a machine responds to the ARP requests from both Ethernet interfaces of the same subnet.

To avoid the ARP flux issue:

  1. Log in to the affected node.

  2. Set the following network parameters:

    sysctl -w net.ipv4.conf.all.arp_ignore=2
    sysctl -w net.ipv6.conf.all.arp_ignore=2
    

    This configuration enables responding to the ARP requests only if the target IP is a local address that is configured on the incoming interface and, together with the sender IP address, is part of the same subnet on this interface.