Ok, so this is something that will probably only affect a small amount of people, but is totally frustrating with me an my ISP's...   Gratuitous arp   So here is the scenario... we have a fibre based ISP that will not 'update' the arp table when it sees a packet coming with the IP address if it has a secondary IP address.   The first IP always works, but in order for me to have additional IP addresses (secondary on the Cisco router), then I run a Linux server (which is what the Meraki MX is), and send an 'arping' while spoofing the mac address.  This is a pretty crappy workaround, and of course on my switch I get error logs indicating that the mac address is flapping between ports.   This is a 5 minute fix... any 1:1 or 1:many nat IP's should do this automatically, and maybe once an hour or something like that.   Easy fix Easy to implement Risk to implement low   This is low hanging fruit ... View more