1. A logic device for intercepting a data flow from a network source to a network destination, the logic device comprising: a data store holding a set of compliance rules and corresponding actions wherein at least one of the set of compliance rules is a temporary compliance rule valid for a predetermined period; a packet inspector configured to inspect the intercepted data flow and identify from the data store a temporary compliance rule associated with the inspected data flow; and a packet filter configured to when the data flow is identified as being associated with the temporary compliance rule, carry out an action with respect to the data flow corresponding to the temporary compliance rule while the temporary compliance rule is valid.