3.2b — Jump Server, Proxies, Load Balancers

Jump server

Hardened device on the internal network, reachable from outside, used as the single controlled entry point to manage internal systems.

Jump server risk

Single chokepoint into the internal network; a high-value target requiring MFA, strict logging, and minimal other services.

Proxy server

Sits between client and destination, making requests on the client's behalf.

Explicit proxy

Client is configured with the proxy's address; the client knows it's there.

Transparent proxy

Client has no configuration and no awareness; traffic is intercepted automatically.

Forward proxy

Sits in front of internal clients, controls/inspects outbound traffic to the internet. Protects the client.

Reverse proxy

Sits in front of an internal server, controls/inspects inbound traffic from the internet. Protects and hides the server.

Open proxy

Publicly available proxy run by an unknown third party. Security risk: can inject ads/malware, bypasses your own controls.

NAT as a proxy

Translates internal/external IP addresses on internet-facing routers; the simplest, most common proxy form.

Load balancer

Distributes traffic across multiple servers for efficiency and fault tolerance.

TCP offloading

Load balancer maintains persistent TCP sessions instead of the backend server recreating one per user.

SSL/TLS offloading

Load balancer handles encryption/decryption centrally; traffic to backend servers may then travel decrypted internally, so that segment must be secured.

Content switching

Load balancer routes requests to specific servers based on request type.

Active/active load balancing

All backend servers handle traffic simultaneously; each must be able to absorb full load if a partner fails.

Active/passive load balancing

Some servers standby, activated only if an active server fails.

Sensor and collector

Sensors gather traffic statistics/logs from devices; a collector aggregates that data centrally.

SIEM (Security Information and Event Manager)

Aggregates, correlates, and reports on log/event data from many diverse device types.