Apache configuration

[https://httpd.apache.org/ Apache] is probably the webserver used most with MediaWiki.

PHP as Apache Module
MediaWiki is written to use as an Apache module. Your PHP is probably configured as a module if you start with URLs like this: example.com/index.php/Main_Page

You can check which configuration and version of PHP you have by viewing your wiki's Special:Version page, or with [http://php.net/phpinfo phpinfo].

PHP as CGI
If PHP is running as a CGI, you will have "ugly" URLs by default, but you can still implement.

Spiders and bots
You really should use a file to tell well-behaved spiders not to download dynamically generated pages (edit pages, for instance). This can reduce the load on your webserver, preserve your bandwidth, and prevent duplicate content issues with search engines. However, malicious bots could tie up your webserver and waste your bandwidth by downloading a large volume of pages extremely quickly. Request throttling can help protect against this.