a <b>notBefore</b> time and an optional <b>notAfter</b> time. The current time should fall between these two values, but the interval between the two times may be only a few seconds. In practice the OCSP responder and clients clocks may not be precisely synchronised and so such a check may fail. To avoid this the <b>-validity_period</b> option can be used to specify an acceptable error range in seconds, the default value is 5 minutes.</p>

<p>If the <b>notAfter</b> time is omitted from a response then this 