Syntax: auth_http_pass_client_cert on | off; Default: auth_http_pass_client_cert off; Context: mail, server This directive appeared in version 1.7.11. Appends the “Auth-SSL-Cert” header with the client certificate in the PEM format (urlencoded) to requests sent to the authentication server.

Syntax: auth_http_header header value; Default: — Context: mail, server Appends the specified header to requests sent to the authentication server. This header can be used as the shared secret to verify that the request comes from nginx. For example: auth_http_header X-Auth-Key "secret_string";

Syntax: auth_http URL; Default: — Context: mail, server Sets the URL of the HTTP authentication server. The protocol is described below.

Syntax: auth_basic_user_file file; Default: — Context: http, server, location, limit_except Specifies a file that keeps user names and passwords, in the following format: # comment name1:password1 name2:password2:comment name3:password3 The file name can contain variables. The following password types are supported: encrypted with the crypt() function; can be generated using the “htpasswd” utility from the Apache HTTP Server distribution or the “openssl passwd” command; h

Syntax: auth_basic string | off; Default: auth_basic off; Context: http, server, location, limit_except Enables validation of user name and password using the “HTTP Basic Authentication” protocol. The specified parameter is used as a realm. Parameter value can contain variables (1.3.10, 1.2.7). The special value off allows cancelling the effect of the auth_basic directive inherited from the previous configuration level.

Syntax: ancient_browser_value string; Default: ancient_browser_value 1; Context: http, server, location Sets a value for the $ancient_browser variables.

Syntax: ancient_browser string ...; Default: — Context: http, server, location If any of the specified substrings is found in the “User-Agent” request header field, the browser will be considered ancient. The special string “netscape4” corresponds to the regular expression “^Mozilla/[1-4]”.

Syntax: allow address | CIDR | unix: | all; Default: — Context: stream, server Allows access for the specified network or address. If the special value unix: is specified, allows access for all UNIX-domain sockets.

Syntax: allow address | CIDR | unix: | all; Default: — Context: http, server, location, limit_except Allows access for the specified network or address. If the special value unix: is specified (1.5.1), allows access for all UNIX-domain sockets.

Syntax: alias path; Default: — Context: location Defines a replacement for the specified location. For example, with the following configuration location /i/ { alias /data/w3/images/; } on request of “/i/top.gif”, the file /data/w3/images/top.gif will be sent. The path value can contain variables, except $document_root and $realpath_root. If alias is used inside a location defined with a regular expression then such regular expression should contain captures and alias s