Win2K services accessing the ‘Net !

Hi,

Eversince the installation of Win2K, my firewall (Sygate Personal Firewall Pro) constantly reports all sorts of programs wanting to access the ‘Net via my Cable connection. In particular:

SERVICES.EXE
NTOSKRNL.EXE
LSASS.EXE

(1) Why dothese system services require access to the ‘Net?

(2) Would it be safe to deny these and other services access to the ‘Net?

(3) Does anyone know the absolute minimum services required to access the ‘Net?

Thanks in advance.
Godzillex