DFIR services are advisory services that help clients identify the extent of, and deal with, events and requirements such as security and IT incident investigations, forensic response and triage, and security breaches. They are typically offered by firms on a retainer-based service model, but on-demand or emergency services are also available. A retainer-based service contract encompasses a wide variety of terms and conditions, and is meant to dovetail with the client organization’s documented IR processes and procedures. DFIR services are commonly known as IR services in the industry. Providers often refer to their offerings as combinations of DF, IR and proactive or reactive security services, or just as response services.