While IDSs are able to detect intrusions, they have very little capability in blocking such an attack.

In the briefing, the general started to describe how expensive, advanced equipment for detecting intrusions had been installed or used in ways that made them less effective.

Rather than attempting to detect intrusions at the network interface level (as in network intrusion detection systems), Open Source Tripwire detects changes to file system objects.

While useful for detecting intrusions after the event, it can also serve many other purposes, such as integrity assurance, change management, and policy compliance.

Many developers are also responding to the explosion of wireless networking with products that detect unauthorized Wi-Fi intrusions.

Many firewalls detect attempted intrusions.

Furthermore network monitoring tools can be used to detect intrusions or suspicious traffic on both large and small networks.

Sensors: Devices which detect intrusions.

Engineers plan and conduct technical surveillance inspections to detect and nullify clandestine intrusions.

The Revenue Service is now in the process of testing extra safeguards to detect unauthorized intrusions in the future.