FortiManager - Allow us to specify DynDNS instead of IP for connection to firewalls.

[Annie]

We have a bunch of firewalls set to DHCP instead of static IPs.  Sometimes the firewalls are able to connect into FortiManager and update their IPs, sometimes not.  Why can't we simply set them to DynDNS instead of by IP in FortiManager?  This is supported on FortiConcentrator for connecting to VPN tunnels.  Why not on FortiManager?  And if it is supported, how do you set it up?  To Clarify - I mean so that FortiManager can connect to the firewalls.