A forward proxy works for the person making requests. It is what people mean by "a proxy" when they talk about changing an IP address, and it is what proxy services sell.
A reverse proxy works for the site owner. Visitors connect to it without knowing, and it passes requests to the real servers behind it, adding caching, load balancing and protection against attacks. Content delivery networks are large reverse proxies.
The two often sit on the same request. When you fetch a page through a proxy service, the request leaves through a forward proxy, crosses the internet, and is very often received by a reverse proxy in front of the site. The reverse proxy is where rate limits, captchas and bot checks are usually applied, which is why it matters to anyone who collects data.
Questions about forward and reverse proxy
Which kind does a proxy service sell?
Forward proxies. You are the client, and the proxy makes requests to websites on your behalf.
Is a content delivery network a proxy?
It is a reverse proxy: it sits in front of websites and answers visitors for them. Site owners choose it; visitors do not set anything up.
Related terms
- Proxy server
- A proxy server is a computer that passes your requests on to a website, so the website sees the proxy's IP address and not yours.
- Proxy and VPN
- A VPN sends all of a device's traffic through one encrypted tunnel. A proxy is set per program and can use a different IP for each request.
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