jumphosts

A jumphost, also known as a jump server or bastion host, is a hardened gateway positioned at the boundary between an exposed network and a private management network. It provides a controlled entry point for administrators and automated systems to reach hosts within a private infrastructure without exposing those hosts directly to the internet.

Typically placed in a demilitarized zone or public subnet, the jumphost is the only host reachable from outside. Administrators authenticate to the jumphost using strong methods such as SSH keys and multi-factor authentication, then connect to target internal hosts using permitted management protocols like SSH or RDP. Access is often restricted by source IP, time windows, and role-based policies. Comprehensive logging and, where feasible, session recording help maintain an audit trail of all activity.

Security considerations include minimizing surface area, disabling unnecessary services, and hardening the operating system. Enforce MFA, use unique credentials or per-user keys, rotate credentials regularly, and apply strict firewall and network segmentation. Centralized access control, regular monitoring, and alerting on anomalous sessions are common best practices. Consider isolating the jumphost from direct outbound access to internal networks and implementing least-privilege access for management tasks.

Deployment patterns vary. Organizations may use a single or clustered jumphost to manage multiple targets, with high availability configurations to avoid a single point of failure. In cloud environments, managed alternatives such as dedicated bastion services or session managers are available (for example, AWS Session Manager, Azure Bastion, and Google Cloud IAP), which reduce the need to open direct management ports to internal hosts.

Overall, jumphosts centralize and audit privileged access, improve network security, and simplify policy enforcement while requiring careful design to avoid bottlenecks and single points of failure.