Avoiding ARP Flux in Multi-Interface Linux Hosts
By Stefano GridelliJanuary 17, 2018Linux
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A Linux host that has many Ethernet interfaces on the same subnet is subject to the ARP Flux problem.
The ARP Flux problem occurs when a host replies to ARP requests for interfaces on the same subnet, from any interface on that same subnet. In most cases, this behavior is not a problem. However, in specific cases, ARP Flux generates unexpected behavior of applications due to incorrect mapping between IPv4 addresses and MAC addresses.

The ARP Protocol
The Address Resolution Protocol (ARP) is used to translate an IPv4 address into a MAC address, allowing Layer 2 communications to occur (e.g Ethernet and WiFi). When a source host has to send an IPv4 packet to a destination host on the same subnet, it executes an ARP request to get the MAC address of the destination host. The source host will send an ARP request to the Ethernet broadcast address ff:ff:ff:ff:ff:ff. All of the hosts on the subnet will receive the ARP request that was broadcasted, but, only the destination host will answer to the ARP request with the MAC address associated with its IPv4 address.

Avoiding ARP Flux in Multi-Interface Linux Hosts

https://netbeez.net/blog/avoiding-arp-flux-in-multi-interface-linux-hosts/

The ARP Flux problem occurs when a host replies to ARP requests for interfaces on the same subnet, from any interface on that same subnet. In most cases, this behavior is not a problem. However, in specific cases, ARP Flux generates unexpected behavior of applications due to incorrect mapping between IPv4 addresses and MAC addresses.