Time Based Rules¶
Time based rules allow firewall rules to activate during specified days and/or time ranges. Time based rules function the same as any other rule, except they are effectively not present in the ruleset outside of their scheduled times.
Time Based Rules Logic¶
When dealing with time-based rules, the schedule determines when to apply the action specified in the firewall rule. When the current time or date is not covered by the schedule, the firewall acts as if the rule is not there. For example, a rule that passes traffic on Saturdays will only block it on other days if a separate block rule exists underneath it. The rules are processed from the top-down, the same as other firewall rules. The first match is used, and once a match is found, that action is taken if the rule is in schedule, and no other rules are evaluated.
Remember when using schedules that the rule will have no effect outside of their scheduled times. The rule will not have its action reversed because the current time is not within the scheduled time. Failing to account for this behavior could result in giving clients unintended access outside of the defined time ranges in a schedule.
Configuring Schedules for Time Based Rules¶
Schedules must be defined before they can be used on firewall rules. Schedules are defined under Firewall > Schedules, and each schedule can contain multiple time ranges. In the following example, a company wants to deny access to HTTP during business hours, and allow it all other times of the day.
Defining Times for a Schedule¶
To add a schedule:
- Navigate to Firewall > Schedules
- Click Add to bring up the schedule editing screen, as seen in Figure Adding a Time Range.
- Enter a Schedule Name. This is the name that will appear in the selection
list for use in firewall rules. Much like alias names, this name must only
contain letters and digits, no spaces. For example:
- Enter a Description of this schedule, such as
Normal Business Hours.
- Define one or more time ranges:
- Set the Month by selecting a specific month and days, or by clicking the day of the week header for weekly recurring schedules.
- Choose a Start Time and Stop Time which control when the rule is active on the selected days. The time cannot cross midnight on any day. A full day is 0:00 to 23:59.
- Enter an optional Time Range Description for this specific range, e.g.
- Click Add Time to add the choice as a range
- Repeat Month, Time, and steps for additional ranges
- Click Save
A schedule can apply to specific days, such as September 2, 2016, or to days of the week, such as Monday-Wednesday. To select any given day within the next year, choose the Month from the drop-down list, then click on the specific day or day numbers on the calendar. To select a day of the week, click its name in the column headers.
For this example, click on Mon, Tue, Wed, Thu, and Fri. This will make the schedule active for any Monday-Friday, regardless of the month. Now select the time for this schedule to be active, in 24-hour format. The hours for this example business are 9:00 to 17:00 (5pm). All times are given in the local time zone.
Once the time range has been defined, it will appear in the list at the bottom of the schedule editing screen, as in Figure Added Time Range.
To expand on this setup, there may be a half day on Saturday to define, or maybe the shop opens late on Mondays. In that case, define a time range for the identical days, and then another range for each day with different time ranges. This collection of time ranges will be the full schedule.
Once the schedule entry has been saved, the browser will return to the schedule list, as in Figure Schedule List After Adding. This schedule will now be available for use in firewall rules.
Using the Schedule in a Firewall Rule¶
To create a firewall rule employing this schedule, create a new rule on the desired interface. See Adding a firewall rule and Configuring firewall rules for more information about adding and editing rules. For this example, add a rule to reject TCP traffic on the LAN interface from the LAN subnet to any destination on the HTTP port. In the advanced options for the rule, locate the Schedule setting and choose the BusinessHours schedule, as in Figure Choosing a Schedule for a Firewall Rule.
After saving the rule, the schedule will appear in the firewall rule list along with an indication of the schedule’s active state. As shown in Figure Firewall Rule List with Schedule, this is a reject rule, and the schedule column indicates that the rule is currently in its active blocking state because it is being viewed at a time within the scheduled range. If the mouse cursor hovers over the schedule state indicator, a tooltip is displayed by the firewall showing how the rule will behave at the current time. Since this is being viewed inside of the times defined in the BusinessHours schedule, this will say “Traffic matching this rule is currently being denied”. If there is a pass rule that would match the traffic out on port 80 from the LAN net after this rule, then it would be allowed outside of the scheduled hours.
Now that the rule is defined, test it both inside and outside of the scheduled times to ensure that the desired behavior is enacted.
By default, states are cleared for active connections permitted by a scheduled rule when the schedule expires. This shuts down access for anyone allowed by the rule while it was active. To allow these connections to remain open, check Do not kill connections when schedule expires under System > Advanced on the Miscellaneous tab.