WAN ARP Scope? - same default gateway


#1

This may be a dumb question, but what kind of access scope is applied to the WAN ARP cache? Does each WAN link maintain its own ARP entries or are they shared in a global WAN ARP cache? Or is there just one big ARP cache that is shared by WAN and LAN?

I ask because both of my WAN links use the same default gateway. I did a packet capture and found that my ISP has the same gateway IP assigned to two different Mac addresses. Since I was under the impression that there could/should only be one unique MAC address per IP (I understand that there can be many IPs associated to a single Mac), will the Peplink be able to keep the two paths to the same IP straight? Or will it use the most recent MAC address for both WANs? Or does it see this as a duplicate IP address and start doing something else (like drop packets or run some kind of discovery)?

Somewhat along the same lines - if I add a static ARP entry for the gateway IP, will both WANs use the addresses that I configure?


#2

The ARP entries are tie to WAN interface, so Peplink allows 2 same Gateway IP with different MAC Address on different WANs and able to recognize each of these Gateway IP with associated MAC Address for packet forwarding.

Of course, whenever possible we will try to avoid such setup as that could be confused when comes to troubleshooting. :unamused: