What Is a Proxy Server? How It Works

Q: What is a proxy server and how does it work?

A proxy server is an intermediary that forwards requests on your behalf. Instead of connecting directly to a website, your device connects to the proxy, which makes the request and returns the response. Because the destination sees the proxy address rather than yours, a proxy can change the visible IP, filter, and cache content. Proxies usually work at the application level.

Q: What is the difference between a forward proxy and a reverse proxy?

A forward proxy sits in front of clients and represents them to the internet, hiding or changing the client address for filtering, caching, or location. A reverse proxy sits in front of servers and represents them to clients, handling TLS, caching, and load balancing across backend servers. They are mirror images: forward proxies protect the client, reverse proxies protect the server.

Q: What is a transparent proxy?

A transparent proxy intercepts your traffic without any configuration on your side, often on corporate, school, or some ISP networks. Your requests are silently routed through it, which is how those networks enforce filtering or caching. You did not choose to use it and may not know it is there, which is why it is called transparent, unlike a normal forward proxy you set up deliberately.

Q: What are the different types of proxy servers?

Proxies can be grouped by role and by protocol. By role there are forward proxies for clients, reverse proxies for servers, and transparent proxies that intercept silently. By protocol there are HTTP and HTTPS proxies for web traffic and general-purpose SOCKS proxies that can carry many kinds of traffic. They differ in what they represent and what protocols they handle.

Q: What is the difference between a proxy server and a VPN?

Both change the address the internet sees, but at different levels. A proxy usually handles one application or protocol and often does not encrypt traffic, so it changes your apparent IP without protecting the data. A VPN creates an encrypted tunnel for the whole device, covering every app. A proxy is lighter and app-specific, a VPN is system-wide and encrypted.

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An Intermediary Between You and the Internet
A proxy server is a computer that sits in the middle of a connection and forwards requests on behalf of something else. Instead of your device talking directly to a website, it talks to the proxy, and the proxy makes the request and passes the response back. Because the destination sees the connection coming from the proxy, the proxy can change what IP address is visible, filter or cache content, and control what is allowed through.
You can check whether the address you are presenting to the internet looks like a proxy or datacenter connection with our VPN and Proxy Detector, which inspects the network an IP belongs to.
How a Proxy Server Works
When you configure a proxy, your requests are sent to it first. The proxy opens its own connection to the target, retrieves the response, and returns it to you. The target only ever sees the proxy address, not yours, which is the core of how a proxy changes the apparent source of traffic. Proxies typically operate at the application level, often for HTTP and HTTPS web traffic or as a general-purpose SOCKS proxy, rather than capturing everything your device sends.
Forward Proxy vs Reverse Proxy
A forward proxy sits in front of clients and represents them to the internet. It is what most people mean by proxy: it hides or changes the client address and is used for filtering, caching, or accessing content through a different location. A reverse proxy sits in front of servers and represents them to clients. When you visit a large site, you are often talking to a reverse proxy that handles TLS, caches responses, and spreads load across many backend servers. Software such as Nginx is commonly used as a reverse proxy. The two are mirror images: a forward proxy protects and represents the client, a reverse proxy protects and represents the server.
What Is a Transparent Proxy?
A transparent proxy intercepts your traffic without you configuring anything, often on a corporate, school, or some ISP networks. Your requests are silently routed through it, which is how those networks enforce content filtering or caching. You did not opt in and may not know it is there, hence transparent. By contrast, a normal forward proxy requires the client to be set up to use it deliberately.
Proxy Server vs VPN
A proxy and a VPN both change the address the internet sees, but they work at different levels. A proxy usually handles a single application or protocol and often does not encrypt your traffic, so it changes your apparent IP but does not protect the data in transit. A VPN creates an encrypted tunnel for your entire device, covering every app. A proxy is lighter and app-specific, a VPN is heavier and system-wide and encrypted. For a full side-by-side, see our VPN vs proxy guide. A CDN is a related idea built from reverse proxies, but aimed at delivering a site fast rather than protecting a client.
Frequently Asked Questions
What is a proxy server and how does it work?
A proxy server is an intermediary that forwards requests on your behalf. Instead of connecting directly to a website, your device connects to the proxy, which makes the request and returns the response. Because the destination sees the proxy address rather than yours, a proxy can change the visible IP, filter, and cache content. Proxies usually work at the application level.
What is the difference between a forward proxy and a reverse proxy?
A forward proxy sits in front of clients and represents them to the internet, hiding or changing the client address for filtering, caching, or location. A reverse proxy sits in front of servers and represents them to clients, handling TLS, caching, and load balancing across backend servers. They are mirror images: forward proxies protect the client, reverse proxies protect the server.
What is a transparent proxy?
A transparent proxy intercepts your traffic without any configuration on your side, often on corporate, school, or some ISP networks. Your requests are silently routed through it, which is how those networks enforce filtering or caching. You did not choose to use it and may not know it is there, which is why it is called transparent, unlike a normal forward proxy you set up deliberately.
What are the different types of proxy servers?
Proxies can be grouped by role and by protocol. By role there are forward proxies for clients, reverse proxies for servers, and transparent proxies that intercept silently. By protocol there are HTTP and HTTPS proxies for web traffic and general-purpose SOCKS proxies that can carry many kinds of traffic. They differ in what they represent and what protocols they handle.
What is the difference between a proxy server and a VPN?
Both change the address the internet sees, but at different levels. A proxy usually handles one application or protocol and often does not encrypt traffic, so it changes your apparent IP without protecting the data. A VPN creates an encrypted tunnel for the whole device, covering every app. A proxy is lighter and app-specific, a VPN is system-wide and encrypted.
Last updated: April 2026