Dynamic DNS and WAN failover

I am using a Balance 20 as a WAN failover device. WAN1 is primary WAN2 is backup. Both WANs use static IPs. Currently I have a DNS host entry on a public DNS server pointing to WAN1. However, if WAN1 goes down I would like it to point to WAN2. I am thinking of using Dynamic DNS to implement this, however the documentation seems to imply that Peplink’s implementation of Dynamic DNS only works with dynamic wan IPs (DHCP). My question: If WAN1 goes down, and WAN2 comes up, if I have WAN2 configured for Dynamic DNS, will it notify www.dynamicdns.org of an IP address change for a host? Even it the IP address for WAN2 is static? Or does it only triggered by DHCP changes?

You are referring to inbound load balancing/failover. The Balance 210 and up models have a built-in authoritative DNS server to accomplish this. This is explained here in our knowledge base.

Before I posted my question, I had already read the FAQs on inbound load balancing/fail over using other Balance models. I do realize that using a built in authoritative DNS is one way of doing it. However as stated in my original post, I have a Balance 20 which does not have an authoritative DNS. My question specifically is: What is the behavior of WAN2 if it has a static IP but has been configured with a Dynamic DNS account? When it comes up, will it notify a dynamic dns service? If so, this would be different way of implementing inbound failover (not load balancing obviously). Before I go through the trouble of setting up a dynamic dns account and running the test myself, I wanted to ask a technician at Peplink what the behavior would be. Its a relatively simple question. However, the answer is not in the FAQs or on previous posts.

Dynamic DNS is designed to be used with Dynamic IP’s, hence the name and the Balance will send out an update when its WAN IP changes. Since yours is already static, no update will get sent out. Could you explain how the DNS host entry would get updated via this method?