Firewall schedules control when policies are in effect. When you add a security policy on a FortiGate unit you need to set a schedule to determine the time frame in which that the policy will be functioning. While it is not set by default, the normal schedule would be always. This would mean that the policy that has been created is always function and always policing the traffic going through the FortiGate.

The time component of the schedule is based on a 24 hour clock notation or military time as some people would say.

There are two types of schedules: One-time schedules and recurring schedules.

One-Time schedules are in effect only once for the period of time specified in the schedule. This can be useful for testing to limit how long a policy will be in effect in case it is not removed, or it can be used for isolated events such as a conference where you will only need a temporary infrastructure change for a few days.

The time frame for a One-time schedule is configured by using a start time which includes, Year | Month | Day | Hour | Minute and a Stop time which includes the same variables. So while the frequency of the schedule is only once it can last anywhere from 1 minute to multiple years.

Recurring schedules are in effect repeatedly at specified times of specified days of the week. The Recurring schedule is based on a repeating cycle of the days of the week as opposed to every x days or days of the month. This means that you can configure the schedule to be in effect on Tuesday, Thursday, and Saturday but not every 2 days or on odd numbered days of the month.

If a recurring schedule has a stop time that is earlier than the start time, the schedule will take effect at the start time but end at the stop time on the next day. You can use this technique to create recurring schedules that run from one day to the next.

You want to schedule the use of Skype to only between noon (12:00) and 1 p.m. (13:00).

You could create a schedule that allows Skype traffic:

Or you could have a schedule that blocks Skype traffic:

Either way is effective for the task but other factors may make one method work better than another in certain situations of it could be just a preference in approach.