Definition
A jump server, also known as a bastion host or jump box, is a specially secured computer that acts as a single point of access to a private network from an external network. It is designed to withstand attacks and is the only system that external users can connect to directly. All other internal systems are protected behind this hardened gateway, enforcing strict access controls and logging. This architecture significantly reduces the attack surface by minimizing the number of entry points into the sensitive internal environment. For example, a cybersecurity analyst might use a jump server to remotely access servers in a company's data center without exposing those servers directly to the internet. Unlike a simple VPN, a jump server typically provides command line access and is not intended for general internet browsing. This concept is frequently covered in CompTIA Security+, CySA+, and CISSP certification studies.