FortiGate DOS Policy

Hi All,

Iv recently started looking at the DOS policy on the Fortigate firewalls, I was wondering if anyone had any good articles or learning resources which cover this area?

Iv taken a look at this link and my current employers DOS configurations:-

https://help.fortinet.com/fos50hlp/52data/Content/FortiOS/fortigate-firewall-52/Examples/Example-%20DoS%20Policy.htm

I was wondering if DOS configuration would largely be the same in most organisations and if the default values should be left alone or (as i would think) if it depends on the amount of traffic currently being handled by the firewall.

Has anyone known DOS policies causing problems for legitimate traffic and given the Fortigate options seem quite basic, would it be recommended to have a dedicated appliance to handle this/have your ISP provide the service as I have done in previous roles.

Thanks for any help you are able to provide.