1This matches if the packet arrival time/date is within a given range. All 2options are optional, but are ANDed when specified. All times are interpreted 3as UTC by default. 4.TP 5\fB\-\-datestart\fP \fIYYYY\fP[\fB\-\fP\fIMM\fP[\fB\-\fP\fIDD\fP[\fBT\fP\fIhh\fP[\fB:\fP\fImm\fP[\fB:\fP\fIss\fP]]]]] 6.TP 7\fB\-\-datestop\fP \fIYYYY\fP[\fB\-\fP\fIMM\fP[\fB\-\fP\fIDD\fP[\fBT\fP\fIhh\fP[\fB:\fP\fImm\fP[\fB:\fP\fIss\fP]]]]] 8Only match during the given time, which must be in ISO 8601 "T" notation. 9The possible time range is 1970-01-01T00:00:00 to 2038-01-19T04:17:07. 10.IP 11If \-\-datestart or \-\-datestop are not specified, it will default to 1970-01-01 12and 2038-01-19, respectively. 13.TP 14\fB\-\-timestart\fP \fIhh\fP\fB:\fP\fImm\fP[\fB:\fP\fIss\fP] 15.TP 16\fB\-\-timestop\fP \fIhh\fP\fB:\fP\fImm\fP[\fB:\fP\fIss\fP] 17Only match during the given daytime. The possible time range is 00:00:00 to 1823:59:59. Leading zeroes are allowed (e.g. "06:03") and correctly interpreted 19as base-10. 20.TP 21[\fB!\fP] \fB\-\-monthdays\fP \fIday\fP[\fB,\fP\fIday\fP...] 22Only match on the given days of the month. Possible values are \fB1\fP 23to \fB31\fP. Note that specifying \fB31\fP will of course not match 24on months which do not have a 31st day; the same goes for 28- or 29-day 25February. 26.TP 27[\fB!\fP] \fB\-\-weekdays\fP \fIday\fP[\fB,\fP\fIday\fP...] 28Only match on the given weekdays. Possible values are \fBMon\fP, \fBTue\fP, 29\fBWed\fP, \fBThu\fP, \fBFri\fP, \fBSat\fP, \fBSun\fP, or values from \fB1\fP 30to \fB7\fP, respectively. You may also use two-character variants (\fBMo\fP, 31\fBTu\fP, etc.). 32.TP 33\fB\-\-kerneltz\fP 34Use the kernel timezone instead of UTC to determine whether a packet meets the 35time regulations. 36.PP 37About kernel timezones: Linux keeps the system time in UTC, and always does so. 38On boot, system time is initialized from a referential time source. Where this 39time source has no timezone information, such as the x86 CMOS RTC, UTC will be 40assumed. If the time source is however not in UTC, userspace should provide the 41correct system time and timezone to the kernel once it has the information. 42.PP 43Local time is a feature on top of the (timezone independent) system time. Each 44process has its own idea of local time, specified via the TZ environment 45variable. The kernel also has its own timezone offset variable. The TZ 46userspace environment variable specifies how the UTC-based system time is 47displayed, e.g. when you run date(1), or what you see on your desktop clock. 48The TZ string may resolve to different offsets at different dates, which is 49what enables the automatic time-jumping in userspace. when DST changes. The 50kernel's timezone offset variable is used when it has to convert between 51non-UTC sources, such as FAT filesystems, to UTC (since the latter is what the 52rest of the system uses). 53.PP 54The caveat with the kernel timezone is that Linux distributions may ignore to 55set the kernel timezone, and instead only set the system time. Even if a 56particular distribution does set the timezone at boot, it is usually does not 57keep the kernel timezone offset - which is what changes on DST - up to date. 58ntpd will not touch the kernel timezone, so running it will not resolve the 59issue. As such, one may encounter a timezone that is always +0000, or one that 60is wrong half of the time of the year. As such, \fBusing \-\-kerneltz is highly 61discouraged.\fP 62.PP 63EXAMPLES. To match on weekends, use: 64.IP 65\-m time \-\-weekdays Sa,Su 66.PP 67Or, to match (once) on a national holiday block: 68.IP 69\-m time \-\-datestart 2007\-12\-24 \-\-datestop 2007\-12\-27 70.PP 71Since the stop time is actually inclusive, you would need the following stop 72time to not match the first second of the new day: 73.IP 74\-m time \-\-datestart 2007\-01\-01T17:00 \-\-datestop 2007\-01\-01T23:59:59 75.PP 76During lunch hour: 77.IP 78\-m time \-\-timestart 12:30 \-\-timestop 13:30 79.PP 80The fourth Friday in the month: 81.IP 82\-m time \-\-weekdays Fr \-\-monthdays 22,23,24,25,26,27,28 83.PP 84(Note that this exploits a certain mathematical property. It is not possible to 85say "fourth Thursday OR fourth Friday" in one rule. It is possible with 86multiple rules, though.) 87