407 Proxy Authentication Required

Written by Evert Pot - - Aggregated on Tuesday January 15, 2019

407 Proxy Authentication Required is an error a HTTP proxy returns if it requires authentication. It’s really similar to 401 Unauthorized.


HTTP/1.1 407 Proxy Authentication Required
Proxy-Authenticate: Basic; realm="Secured area"

As you can see above, the response looks pretty similar to 401 and can use the same authentication schemes.

This is an example of a client authenticating with a proxy:

GET / HTTP/1.1
Proxy-Authorization: Basic d2VsbCBkb25lOllvdSBmb3VuZCB0aGUgc2Vjb25kIGVhc3RlciBlZ2cK

If a clients connects to a server that requires authentication via a proxy that also requires authentication, both headers might appear in a request:

GET / HTTP/1.1
Proxy-Authorization: Basic ZWFzdGVyIGVnZzpudW1iZXIgdGhyZWUK
Authorization: Bearer c2VuZCBtZSBhIHR3ZWV0IG9yIHNvbWV0aGluZwo


HTTP proxies used to be more common. They can act like local caches or provide an additional layer of security in a corporate environment. These days they are less common for those purposes. Caching is not as needed, and the security layer is more often implemented with a VPN. Most HTTP proxies these days are reverse proxies, which is mostly transparent for HTTP clients.

Basic and Digest authentication for proxies is widely supported by browsers and other HTTP clients.


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