Syntax: imap_auth method ...; Default: imap_auth plain; Context: mail, server Sets permitted methods of authentication for IMAP clients. Supported methods are: login AUTH=LOGIN plain AUTH=PLAIN cram-md5 AUTH=CRAM-MD5. In order for this method to work, the password must be stored unencrypted. external AUTH=EXTERNAL (1.11.6).

Syntax: image_filter_sharpen percent; Default: image_filter_sharpen 0; Context: http, server, location Increases sharpness of the final image. The sharpness percentage can exceed 100. The zero value disables sharpening. Parameter value can contain variables.

Syntax: image_filter_transparency on|off; Default: image_filter_transparency on; Context: http, server, location Defines whether transparency should be preserved when transforming GIF images or PNG images with colors specified by a palette. The loss of transparency results in images of a better quality. The alpha channel transparency in PNG is always preserved.

Syntax: image_filter_jpeg_quality quality; Default: image_filter_jpeg_quality 75; Context: http, server, location Sets the desired quality of the transformed JPEG images. Acceptable values are in the range from 1 to 100. Lesser values usually imply both lower image quality and less data to transfer. The maximum recommended value is 95. Parameter value can contain variables.

Syntax: image_filter_webp_quality quality; Default: image_filter_webp_quality 80; Context: http, server, location This directive appeared in version 1.11.6. Sets the desired quality of the transformed WebP images. Acceptable values are in the range from 1 to 100. Lesser values usually imply both lower image quality and less data to transfer. Parameter value can contain variables.

Syntax: image_filter_buffer size; Default: image_filter_buffer 1M; Context: http, server, location Sets the maximum size of the buffer used for reading images. When the size is exceeded the server returns error 415 (Unsupported Media Type).

Syntax: image_filter_interlace on | off; Default: image_filter_interlace off; Context: http, server, location This directive appeared in version 1.3.15. If enabled, final images will be interlaced. For JPEG, final images will be in “progressive JPEG” format.

Syntax: image_filter off;image_filter test;image_filter size;image_filter rotate 90 | 180 | 270;image_filter resize width height;image_filter crop width height; Default: image_filter off; Context: location Sets the type of transformation to perform on images: off turns off module processing in a surrounding location. test ensures that responses are images in either JPEG, GIF, PNG, or WebP format. Otherwise, the 415 (Unsupported Media Type)

Syntax: ignore_invalid_headers on | off; Default: ignore_invalid_headers on; Context: http, server Controls whether header fields with invalid names should be ignored. Valid names are composed of English letters, digits, hyphens, and possibly underscores (as controlled by the underscores_in_headers directive). If the directive is specified on the server level, its value is only used if a server is a default one. The value specified also applies to all virtual servers listening on

Syntax: if_modified_since off | exact | before; Default: if_modified_since exact; Context: http, server, location This directive appeared in version 0.7.24. Specifies how to compare modification time of a response with the time in the “If-Modified-Since” request header field: off the “If-Modified-Since” request header field is ignored (0.7.34); exact exact match; before modification time of a response is less than or equal to the time in the “If-Modified-Since”