Doubts to configure correct threshold DoS Policy

[fortimaster]

Hi all¡

I would like to protect some of my public HTTPS servers from DoS Attacks. The question I have, is how to check the normal use of my servers under normal conditions so I can configure correct tresholds to adapt them to my scenario. I imagine that each situation has its own circumstances.

For example, to configure TCP_SYN_Flood I have looked the HTTPS sessions stablished with one of my servers in one hour. With "accept" on "firewall action" column (not srv-rst, or close etc) the result is 50 active sessions. For example, a good threshold could be 150 for TCP_SYN_FLOOD (50x3)? 

I use this criterion because I don't know which could be a good way to find this information. Could you help me to set these thresholds correctly and how to get information to do it? Where do you get this information?

Thanks ''¡¡¡¡

[Mrinmoy]

As this varies from network to network there is no chance to set the best settings for your network, you can try checking this document ( Denial of service )

https://docs.fortinet.com/document/fortigate/7.6.0/best-practices/555436/hardening#DoS

[fortimaster]

Thanks for your help. Maybe a good idea is to monitor anomalies for some time to obtain a reference.