Здравствуйте.

Заметил в логах частые запросы на несуществующие страницы:

--------------------- httpd Begin ------------------------

3.66 MB transferred in 1216 responses  (1xx 0, 2xx 523, 3xx 49, 4xx 644, 5xx 0)
      12 Images (0.02 MB),
    1196 Content pages (3.63 MB),
       3 Redirects (0.00 MB),
       5 Other (0.00 MB)

Requests with error response codes
    404 Not Found
       /PMA/main.php: 1 Time(s)
       /PMA/read_dump.phpmain.php: 1 Time(s)
       /PMA2005/main.php: 1 Time(s)
       /PMA2006/main.php: 1 Time(s)
       /admin/PMA2005/main.php: 1 Time(s)
       /admin/PMA2006/main.php: 1 Time(s)
       /admin/db/main.php: 1 Time(s)
       /admin/main.php: 1 Time(s)
       /admin/myadmin/main.php: 1 Time(s)
       /admin/mysql-admin/main.php: 1 Time(s)
       /admin/mysql/main.php: 1 Time(s)
       /admin/mysqladmin/main.php: 1 Time(s)
       /admin/mysqlmanager/main.php: 1 Time(s)
       /admin/p/m/a/main.php: 1 Time(s)
       /admin/pMA/main.php: 1 Time(s)
       /admin/php-my-admin/main.php: 1 Time(s)
       /admin/php-myadmin/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.2.3/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.2.6/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.1/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.4/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.5-pl1/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.5-rc1/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.5-rc2/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.5/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.6-rc1/main.php: 1 Time(s)
       /admin/phpMyAdmin-2.5.6-rc2/main.php: 1 Time(s)
       /admin/phpmanager/main.php: 1 Time(s)
       /admin/phpmy-admin/main.php: 1 Time(s)
       /admin/phpmyadmin/main.php: 1 Time(s)
       /admin/phpmyadmin/read_dump.phpmain.php: 1 Time(s)
       /admin/phpmyadmin2/main.php: 1 Time(s)
       /admin/pma/read_dump.phpmain.php: 1 Time(s)
       /admin/pma2005/main.php: 1 Time(s)
       /admin/pma2006/main.php: 1 Time(s)
       /admin/read_dump.phpmain.php: 1 Time(s)
       /admin/sqladmin/main.php: 1 Time(s)
       /admin/sqlmanager/main.php: 1 Time(s)
       /admin/sqlweb/main.php: 1 Time(s)
       /admin/sysadmin/main.php: 1 Time(s)
       /admin/web/main.php: 1 Time(s)
       /admin/webadmin/main.php: 1 Time(s)
       /admin/webdb/main.php: 1 Time(s)
       /admin/websql/main.php: 1 Time(s)
       /administrator/admin/main.php: 1 Time(s)
       /administrator/db/main.php: 1 Time(s)
       /administrator/dbadmin/main.php: 1 Time(s)
       /administrator/main.php: 1 Time(s)
       /administrator/myadmin/main.php: 1 Time(s)
       /administrator/mysql-admin/main.php: 1 Time(s)
       /administrator/mysql/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.0-pl3/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.0-rc1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.0-rc2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.0-rc3/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.0/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1-pl1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1-pl2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1-pl3/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1-rc1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1-rc2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.2-beta1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.2-pl1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.2-rc1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.3-pl1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.3-rc1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.3/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.4-pl1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.6.4-pl2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.0.2/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.0.3/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.0.4/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.0/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.1-rc1/main.php: 1 Time(s)
       /administrator/phpMyAdmin-2.8.1/main.php: 1 Time(s)
       /mysql/phpMyAdmin-2.8.0/main.php: 1 Time(s)
       /mysql/phpMyAdmin-2.8.1-rc1/main.php: 1 Time(s)
       /mysql/phpMyAdmin-2.8.1/main.php: 1 Time(s)
       /mysql/phpMyAdmin-2.8.2/main.php: 1 Time(s)
       /mysql/phpMyAdmin-2/main.php: 1 Time(s)
       /mysql/phpMyAdmin/main.php: 1 Time(s)
       /mysql/phpMyAdmin2/main.php: 1 Time(s)
       /mysql/phpmanager/main.php: 1 Time(s)
       /mysql/phpmy-admin/main.php: 1 Time(s)
       /mysql/phpmyadmin/main.php: 1 Time(s)
       /mysql/phpmyadmin2/main.php: 1 Time(s)
       /mysql/pma2005/main.php: 1 Time(s)
       /mysql/pma2006/main.php: 1 Time(s)
       /mysql/read_dump.phpmain.php: 1 Time(s)
       /mysql/sqlmanager/main.php: 1 Time(s)
       /mysql/sqlweb/main.php: 1 Time(s)
       /mysql/web/main.php: 1 Time(s)
       /mysql/webadmin/main.php: 1 Time(s)
       /mysql/webdb/main.php: 1 Time(s)
       /mysql/websql/main.php: 1 Time(s)
       /mysqladmin/main.php: 1 Time(s)
       /mysqladmin/read_dump.phpmain.php: 1 Time(s)
       /mysqlmanager/main.php: 1 Time(s)
       /p/m/a/main.php: 1 Time(s)
       /php-my-admin/main.php: 1 Time(s)
       /php-myadmin/main.php: 1 Time(s)
       /phpMyAdmin: 5 Time(s)
       /phpMyAdmin-2.2.3/main.php: 1 Time(s)
       /phpMyAdmin-2.2.3/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.2.6/main.php: 1 Time(s)
       /phpMyAdmin-2.2.7-pl1/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.5.1/main.php: 1 Time(s)
       /phpMyAdmin-2.5.4/main.php: 1 Time(s)
       /phpMyAdmin-2.5.5-pl1/main.php: 1 Time(s)
       /phpMyAdmin-2.5.5-rc1/main.php: 1 Time(s)
       /phpMyAdmin-2.5.5-rc2/main.php: 1 Time(s)
       /phpMyAdmin-2.5.5/main.php: 1 Time(s)
       /phpMyAdmin-2.5.6-rc1/main.php: 1 Time(s)
       /phpMyAdmin-2.5.6-rc2/main.php: 1 Time(s)
       /phpMyAdmin-2.5.6/main.php: 1 Time(s)
       /phpMyAdmin-2.5.6/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.5.7-pl1/main.php: 1 Time(s)
       /phpMyAdmin-2.5.7-pl1/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.5.7/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-alpha/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-alpha2/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-beta1/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-beta2/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-pl1/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-pl2/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-pl3/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-pl3/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.6.0-rc1/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-rc2/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0-rc3/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0/main.php: 1 Time(s)
       /phpMyAdmin-2.6.0/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.6.1-pl1/main.php: 1 Time(s)
       /phpMyAdmin-2.6.1-pl2/main.php: 1 Time(s)
       /phpMyAdmin-2.6.1-pl3/main.php: 1 Time(s)
       /phpMyAdmin-2.6.1-pl3/read_dump.phpmain.php: 1 Time(s)
       /phpMyAdmin-2.8.0/main.php: 1 Time(s)
       /phpMyAdmin-2.8.1-rc1/main.php: 1 Time(s)
       /phpMyAdmin-2.8.1/main.php: 1 Time(s)
       /phpMyAdmin-2.8.2/main.php: 1 Time(s)
       /phpMyAdmin-2/main.php: 1 Time(s)
       /phpMyAdmin/main.php: 1 Time(s)
       /phpMyAdmin2/main.php: 1 Time(s)
       /phpadmin/read_dump.phpmain.php: 1 Time(s)
       /phpmanager/main.php: 1 Time(s)
       /phpmy-admin/main.php: 1 Time(s)
       /phpmyadmin/main.php: 1 Time(s)
       /phpmyadmin/read_dump.phpmain.php: 1 Time(s)
       /phpmyadmin1/read_dump.phpmain.php: 1 Time(s)
       /phpmyadmin2/main.php: 1 Time(s)
       /phpmyadmin2/read_dump.phpmain.php: 1 Time(s)
       /pma2005/main.php: 1 Time(s)
       /pma2006/main.php: 1 Time(s)
       /sql/admin/main.php: 1 Time(s)
       /sql/db/main.php: 1 Time(s)
       /sql/dbadmin/main.php: 1 Time(s)
       /sql/main.php: 1 Time(s)
       /sql/myadmin/main.php: 1 Time(s)
       /sql/p/m/a/main.php: 1 Time(s)
       /sql/pMA/main.php: 1 Time(s)
       /sql/pMA2005/main.php: 1 Time(s)
       /sql/pMA2006/main.php: 1 Time(s)
       /sql/php-my-admin/main.php: 1 Time(s)
       /sql/php-myadmin/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.2.3/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.2.6/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.1/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.4/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.5-pl1/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.5-rc1/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.5-rc2/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.5/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.6-rc1/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.6-rc2/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.6/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.7-pl1/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.5.7/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.6.0-alpha/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.6.0-alpha2/main.php: 1 Time(s)
       /sql/phpMyAdmin-2.6.0-beta1/main.php: 1 Time(s)
    
  ---------------------- httpd End -------------------------

Я так понимаю это сканирование на уязвимые места. Как можно от этого сканирования защититься? Боюсь, что вдруг они что-нибудь всё-таки найдут :)

Это почтовый сервер. Postfix 2.5.5/Apache 2.2.9/MySQL 5.0.51/SquirrelMail 1.4.19/Fail2Ban/Iptables