From mydigitallife.info
When Apache HTTPD web server generates any web pages or error pages, some important information about the version and other details implemented on the system are displayed in th web site server header. For example, the information text may be like this:
Server: Apache/1.3.37 (Unix) mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a PHP-CGI/0.1b
Server: Apache/2.0.53 (Ubuntu) PHP/4.3.10-10ubuntu4 Server at xx.xx.xx.xx Port 80
The line in the server header expose important version and variant information about the Linux operating system and Apache software used on the machine, indirectly expose the possible security holes that are existed to the hackers, or at least make malicious attackers easier to identify your system for available attack points.
To ensure that the Apache HTTP web server does not broadcast this message to the whole world publicly and fix possible security issue, modify these two directives ServerTokes and ServerSignature in httpd.conf configuration file.
