Recognizing that there will be instances where you wish to limit the time(s) of day or day(s) of the week that particular sites can access your network, we have implemented a flexible way to express this in an authorization file rule.
Time limits are enabled by inserting appropriate optional time range specifications in a rule in the authorization file. A time range specification is enclosed in square brackets [ ] and has the following syntax:
time-range [ @ time-range ] [; time-range [ @ time-range ] ... ]
A time-range is a character string which specifies a start time and an end time, separated by a hyphen (-). White space is permitted within a time range, and start and end times may be any of the following formats, but the format must be consistent within a time range.
Specifies an exact time of day in the form hh:mm:ss meridian timezone. Minutes, seconds, meridian, and timezone are optional. If no meridian - AM or PM - is specified, a 24-hour clock is used. Spaces may be used, but are not required. Timezone and meridian may be in either upper- or lower-case, with or without periods. Examples are: 08:15AM (8:15 AM localtime) and 23 gmt (11:00 p.m. GMT).
A date is an absolute month and day, with optional year. Acceptable formats are a month name, day name or ordinal, or month, day, or year in numeric format mm/dd/yy. Day is a valid day name, number (1-31) or ordinal (first through twelfth, excepting second owing to ambiguity). The optional year is a numeric (i.e. 1995 or 95). Examples are: 05/15/95, January fifth, and Dec 31.
Most common abbreviations (non-case-sensitive) for days and months are accepted, with or without a trailing period.
Nonspecific dates/times are interpreted relative to the current time. Acceptable relative times are year, month, day, hour, minute, and second. Specifications follow the rules above.
The date is formed as follows: first, any absolute date and/or time is processed and converted. Using that time as the base, day-of-week specifications are added. Next, relative specifications are used. If a date or day is specified, and no absolute or relative time is given, midnight is used. Finally, a correction is applied so that the correct hour of the day is produced after allowing for daylight savings time adjustments.
To clarify the use of time ranges, we provide some examples below. An example of a time range that allows access any time Monday thru Friday follows:
[ Monday - Friday ]
Because the above time range does not indicate a specific date, it allows access on any Monday, Tuesday, Wednesday, Thursday, or Friday.
More complex date specifications include a qualifier, the `@' character, to specify both a day range and a time range. For example, to allow access via the Eagle during normal business working hours Monday through Friday:
[ Monday - Friday @ 8AM - 4:30PM ]
Multiple time ranges can be specified with the semi-colon. To allow access via the Eagle during normal business working hours and/or during the evening hours of Monday (only), use:
[ Monday - Friday @ 8AM - 4:30PM; Monday @ 4:30PM - 9:00PM ]
This facility is particularly useful when you have to provide short-term access to outsiders, such a service personnel. You do not have to worry about immediately deactivating their accounts when they are finished. This authorization facility prevents them from accessing your system before you are able to update your accounts list. In the next example, the users are limited to accessing your network during a specific 10-day period, at the end of which active connections are stopped, and further access is prevented.
[ December 1, 1995 12:00 - December 10, 1995 16:30 ]