An extranet is a private network that uses the public internet to securely share information between a company and its suppliers, vendors, partners, or customers. It extends a company's intranet to authorized users outside the company. Extranets allow large data exchanges and collaborations like shared catalogs, news, projects, and applications between businesses. While extranets provide benefits of reduced costs and faster processes, they also require significant resources to develop, integrate with legacy systems, and maintain security.