[support] url alias and path auto

Hi, I hope I can explain this clearly enough. Here it goes: I'm having two issues one is, that even using url alias and pathauto modules (Drupal 6) I can still access my post with two different (or more) urls. here an example. /node/5 /node/5/3945 If you need me to give you the real urls let me know. Is there a way to solve this?, should it be done in Drupal, or should I use Nginx or Apache? I have this setup Varnish -> Nginx (serving boost files) -> Apache. thanks a lot for your help. Guillermo.