Proxy Server

A proxy server is an intermediary that sends traffic between a client and a destination instead of connecting them directly. The destination communicates with the proxy’s network address, while the proxy relays requests and responses for the original client.

A forward proxy acts on behalf of a client. An application sends its outbound traffic to the proxy, which can route the connection through another network, apply access rules, or keep the client’s source address from the destination. A reverse proxy sits in front of one or more servers and accepts inbound traffic for them. It can choose a backend, terminate TLS, cache responses, or shield the backend addresses from direct access.

The word “proxy” often means a forward proxy in discussions of privacy, web scraping, network testing, or location-based access. The same basic relay model also appears in corporate gateways, content delivery systems, and application infrastructure. Protocol support matters: an HTTP proxy understands HTTP traffic, while a SOCKS proxy carries a broader range of connections without interpreting the application protocol.

For a practical look at defensive uses, read the role of proxy servers in cybersecurity.

Related terms: forward proxy, reverse proxy, and exit node.