automatic plugin installation

hi,

I am trying to host my WP blogs on a dedicated server that I manage myself instead of a classical web hosting with poor performance.

It is almost up & running but does not yet give full satisfaction.

One of things I would like to improve is the plugin installation.

On my server, I can install a plugin through the internal WP FTP possibility by providing host/login/password

on 1and1 web hosting, it is fully automatic without any FTP password to provide.

Where does this difference come from ? Should I install a specific PHP module ?

thanks for your input

donald