MultiWan & DynDNS, how it works?

[Vetal]

Hello, I am using pfSense 2.1

I have 2 providers with a different public IPs

I've found on DynDNS page (Services: Dynamic DNS client), "Interface to Monitor" combo box has a Gateway Group in addition to common Wan interfaces.

How does it work? Which interface will be published for the domain name ("Hostname") for LB or failover situation?

In ideal world, I'd expect it will pick arbitrary (or a higher tier for failover) one of the WANs. And will update until one of the members is down to publish available Wan. Providing failover in case on of the ISPs went down. Is this a case?

Or it is just a bug and GW group should be filtered out from combo box?

[Vetal]

Actually, it (pfSense 2.1) DynDNS works as a failover  in this respect, properly updating to tier 2 if tier 1 is off. And than back to Tier 1 if it is back again