Simple, desde tu consola haces:
$sudo a2enmod
Which module would you like to enable?
Your choices are: actions asis auth_anon auth_dbm auth_digest auth_ldap cache cern_meta cgid cgi dav_fs dav deflate disk_cache expires ext_filter file_cache headers imap include info ldap mem_cache mime_magic php5 proxy_connect proxy_ftp proxy_http proxy rewrite speling ssl suexec unique_id userdir usertrack vhost_alias
Module name? mime_magic
Module mime_magic installed; run /etc/init.d/apache2 force-reload to enable.
