Nginx 400 Bad Request errors

Here is a excellent tutorial show you how to solve Nginx 400 Bad Request errors:

It seems that we need to increase the size of the header space that nginx needs to process headers. The setting for this is large_client_header_buffers, and the size part of this needs to be big enough to handle the entire cookie header being sent.

We set this to 8K and tried again. Still getting errors!

Putting a little test app together to play with cookie sizes, I quickly find the documentation for large_client_header_buffers and see that it works at the http or the server level. Well, it doesn’t work at the server level at all! That’s where we had it. The same setting at the http level works great though!