You are asked to configure your SRX Series device to block all traffic from certain...

Juniper ATP Geo IP can help to accomplish this task by using geolocation services to determine the geographical location of IP addresses. As IP prefixes get allocated to the countries that you have specified, the Geo IP solution will automatically update the configured firewall policies to block any traffic that is coming from those specific countries.

This is a great solution for blocking specific countries - as it will allow for a more personalized and targeted approach to firewall policies - and thus, to increase the effectiveness of the solution at blocking potential malicious traffic.