This matches if the packet arrival time/date is within a given range. All

options are optional, but are ANDed when specified. All times are interpreted

as UTC by default.

.TP

\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]]]]]

.TP

\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]]]]]

Only match during the given time, which must be in ISO 8601 "T" notation.

The possible time range is 1970-01-01T00:00:00 to 2038-01-19T04:17:07.

.IP

If \-\-datestart or \-\-datestop are not specified, it will default to 1970-01-01

and 2038-01-19, respectively.

.TP

\fB\-\-timestart\fP \fIhh\fP\fB:\fP\fImm\fP[\fB:\fP\fIss\fP]

.TP

\fB\-\-timestop\fP \fIhh\fP\fB:\fP\fImm\fP[\fB:\fP\fIss\fP]

Only match during the given daytime. The possible time range is 00:00:00 to

23:59:59. Leading zeroes are allowed (e.g. "06:03") and correctly interpreted

as base-10.

.TP

[\fB!\fP] \fB\-\-monthdays\fP \fIday\fP[\fB,\fP\fIday\fP...]

Only match on the given days of the month. Possible values are \fB1\fP

to \fB31\fP. Note that specifying \fB31\fP will of course not match

on months which do not have a 31st day; the same goes for 28- or 29-day

February.

.TP

[\fB!\fP] \fB\-\-weekdays\fP \fIday\fP[\fB,\fP\fIday\fP...]

Only match on the given weekdays. Possible values are \fBMon\fP, \fBTue\fP,

\fBWed\fP, \fBThu\fP, \fBFri\fP, \fBSat\fP, \fBSun\fP, or values from \fB1\fP

to \fB7\fP, respectively. You may also use two-character variants (\fBMo\fP,

\fBTu\fP, etc.).

.TP

\fB\-\-contiguous\fP

When \fB\-\-timestop\fP is smaller than \fB\-\-timestart\fP value, match

this as a single time period instead distinct intervals.  See EXAMPLES.

.TP

\fB\-\-kerneltz\fP

Use the kernel timezone instead of UTC to determine whether a packet meets the

time regulations.

.PP

About kernel timezones: Linux keeps the system time in UTC, and always does so.

On boot, system time is initialized from a referential time source. Where this

time source has no timezone information, such as the x86 CMOS RTC, UTC will be

assumed. If the time source is however not in UTC, userspace should provide the

correct system time and timezone to the kernel once it has the information.

.PP

Local time is a feature on top of the (timezone independent) system time. Each

process has its own idea of local time, specified via the TZ environment

variable. The kernel also has its own timezone offset variable. The TZ

userspace environment variable specifies how the UTC-based system time is

displayed, e.g. when you run date(1), or what you see on your desktop clock.

The TZ string may resolve to different offsets at different dates, which is

what enables the automatic time-jumping in userspace. when DST changes. The

kernel's timezone offset variable is used when it has to convert between

non-UTC sources, such as FAT filesystems, to UTC (since the latter is what the

rest of the system uses).

.PP

The caveat with the kernel timezone is that Linux distributions may ignore to

set the kernel timezone, and instead only set the system time. Even if a

particular distribution does set the timezone at boot, it is usually does not

keep the kernel timezone offset - which is what changes on DST - up to date.

ntpd will not touch the kernel timezone, so running it will not resolve the

issue. As such, one may encounter a timezone that is always +0000, or one that

is wrong half of the time of the year. As such, \fBusing \-\-kerneltz is highly

discouraged.\fP

.PP

EXAMPLES. To match on weekends, use:

.IP

\-m time \-\-weekdays Sa,Su

.PP

Or, to match (once) on a national holiday block:

.IP

\-m time \-\-datestart 2007\-12\-24 \-\-datestop 2007\-12\-27

.PP

Since the stop time is actually inclusive, you would need the following stop

time to not match the first second of the new day:

.IP

\-m time \-\-datestart 2007\-01\-01T17:00 \-\-datestop 2007\-01\-01T23:59:59

.PP

During lunch hour:

.IP

\-m time \-\-timestart 12:30 \-\-timestop 13:30

.PP

The fourth Friday in the month:

.IP

\-m time \-\-weekdays Fr \-\-monthdays 22,23,24,25,26,27,28

.PP

(Note that this exploits a certain mathematical property. It is not possible to

say "fourth Thursday OR fourth Friday" in one rule. It is possible with

multiple rules, though.)

.PP

Matching across days might not do what is expected.  For instance,

.IP

\-m time \-\-weekdays Mo \-\-timestart 23:00  \-\-timestop 01:00

Will match Monday, for one hour from midnight to 1 a.m., and then

again for another hour from 23:00 onwards.  If this is unwanted, e.g. if you

would like 'match for two hours from Montay 23:00 onwards' you need to also specify

the \-\-contiguous option in the example above.