How to make a full limitaion connection to mailserver?

duchoang

Hi everyone,
I'm new in checkpoint management. My mail server working behind the checkpoint is recently attacked many times by DoS. The POP3 service receives many connections at a time that makes all mail services suspended.
I'd like to configure a protection at IPS to block any IP that will be accessing to my mail server with exceeding a connection limitation.
Can anyone guide me how to configure the checkpoint?