Rolf,

You were right about security for navigating the hive.  I had to give
permissions at the HKEY_LOCAL_MACHINE\SYSTEM level before I could navigate
further down.

However, this did not fix my problems with OPC.  I still get the same error
message when trying to browse OPC Servers on remote computers.  My next step
is to try getting this to work on a Windows 2000 computer to see if it makes
any difference.

Thanks!

John

>>> Rolf Kalbermatter 01/15/04 03:43AM >>>
"John Howard" <[EMAIL PROTECTED]> wrote:

>If I try to view the registry keys on the remote computer using 'regedt32', I
can not
>view anything below HKEY_LOCAL_MACHINE\SYSTEM, even though I have modified
security for
>the following keys to make sure DCOM should work.
>"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurePipeServers ..."
>I gave "Everyone" full access to these keys just to be sure security wouldn't
be a problem.

I have no experience both with OPC DAQ as well as XP but here it goes:

Windows security is tricky at its best, maybe every security is like that.
However
I do believe that the inability to browse the hive in regedit may have to do
with
the fact that a key has rights to both view as well as enumerate (expand) it.
So in
order to browse to your key you might need to allow on all keys from
HKLM\SYSTEM down
to the one you want to get at the enumerate privilege for the user in
question. There
are actually a whole bunch of different privileges one can request for when
opening a
key. 

Maybe XP has changed somehow that it will in its RPC implementaiton just
enumerate the
keys hierarchy level for hierarchy level until it gets at the one it needs and
that
would fail when the enumerate privilege is not enabled. Or DAQ OPC or Windows
RPC
request one of the many privileges to much when trying to open a key, failing
on that
one although it may not be needed for the operation in question.

As Microsoft has become more concerned with security in the past year or two
such small
but under certain circumstances far reaching modifications to core elements
have become
more the rule than the exception.

Rolf Kalbermatter
CIT Engineering Nederland BV    tel: +31 (070) 415 9190
Treubstraat 7H                           fax: +31 (070) 415 9191
2288 EG Rijswijk http://www.citengineering.com 
Netherlands  mailto:[EMAIL PROTECTED]


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