Apache Reference Manual (11)_PHP Tutorial

ServerRoot directive
Syntax: ServerRoot directory-filename
Default: ServerRoot /usr/local/apache
Context: server config
Status: core
The ServerRoot directive sets the directory in which the server lives. Typically it will contain the subdirectories conf/ and logs/. Relative paths for other configuration files are taken as relative to this directory.
See also the -d option to httpd.
See also the security tips for information on how to properly set permissions on the ServerRoot.
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ServerSignature directive
Syntax: ServerSignature Off | On | EMail
Default: ServerSignature Off
Context: server config, virtual host, directory, .htaccess
Status: core
Compatibility: ServerSignature is only available in Apache 1.3 and later.
The ServerSignature directive allows the configuration of a trailing footer line under server-generated documents (error messages, mod_proxy ftp directory listings, mod_info output, ...). The reason why you would want to enable such a footer line is that in a chain of proxies, the user often has no possibility to tell which of the chained servers actually produced a returned error message.
The Off setting, which is the default, suppresses the error line (and is therefore compatible with the behavior of Apache-1.2 and below). The On setting simply adds a line with the server version number and ServerName of the serving virtual host, and the EMail setting additionally creates a "mailto:" reference to the ServerAdmin of the referenced document.
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ServerTokens directive
Syntax: ServerTokens Minimal|OS|Full
Default: ServerTokens Full
Context: server config
Status: core
Compatibility: ServerTokens is only available in Apache 1.3 and later
This directive controls whether Server response header field which is sent back to clients includes a description of the generic OS-type of the server as well as information about compiled-in modules.