SETTING DDNS FORTINET

Disable the anycast communication for the FortiGuard server (CLI):

config system fortiguard
    set fortiguard-anycast disable
    set protocol udp
end

Configure a dedicated DDNS Server (CLI):
config system fortiguard
    set ddns-server-ip 173.243.138.225
end

config system ddns
    edit 1
        set ddns-server FortiGuardDDNS
        set server-type ipv4
        set ddns-domain "branch.float-zone.com"
        set addr-type ipv4
        set use-public-ip enable
        set monitor-interface "wan1"
    next
end