There are cases when the HTTP proxy must return an error page to the client to indicate certain error conditions. These error messages are stored as files in the directory specified by the error_files_directory attribute, and can be customized by changing the contents of the files in this directory.

Each file contains plain HTML text, but some special macros are provided to dynamically add information to the error page. The following macros can be used:

It is generally recommended not to display error messages to untrusted clients, as they may leak confidential information. To turn error messages off, set the error_silent attribute to TRUE, or strip error files down to a minimum.