Some C/S, Some Direct...???

Just upgraded from GW5.5 to GW6. When GW5.5 was originally installed,
server
did not have an IP address, so PO was configured as DIRECT & users had

directory rights.

Now, I'm on GW6, set PO to C/S & Direct. All users have either NW
Client
4.83sp1 or 3.3.2 SP1, & a valid IP address. However, most clients are

accessing via Direct; only some connect via client server. Can't see
why
this is happening.

If I set PO to C/S only, or take away directory rights, these clients
can't
access GW6 at all. Can't see why this is happening...any ideas? I've
even
tried reinstalling client on several.

Thanks!
Kelly