http://forum.mikrotik.com/t/badly-works-pptp-server/34495/1
http://forum.mikrotik.com/t/servers-running-routeros-3-x-hangs-in-a-randomly-basis/21933/1
http://forum.mikrotik.com/t/very-strange-3-x-4-x-5-x-freeze-and-crash-with-pppoe/22670/1
http://forum.mikrotik.com/t/routeros-radius-client-timeout-pppoe-pcq/34479/1