Problem with CAS redirection to drupal

[Davide D'Amico]

 I need help with my cas configuration..
I have a server ubuntu with tomcat and apache installed.
Under tomcat I have installed CAS server and under apache I have
installed Drupal with the cas module.
When I try to login, the page return in idle.
No error are detected by the log, but I do not manage to go back in drupal.
If I try to call cas from another machine it works and it works also
if I use drupal and in another machine I put CAS server.
So it seems that when they are on the same machine the redirection
doesn't work. But CAS is working fine.
please help me.
Davide D'Amico