UAC - What's that?

User Account Control (UAC) is a security feature introduced with Microsoft's Windows Vista and Windows Server 2008 operating systems, with a more relaxed version also present in Windows 7 and Windows Server 2008 R2. It aims to improve the security of Microsoft Windows by limiting application software to standard user privileges until an administrator authorizes an increase or elevation. In this way, only applications trusted by the user may receive administrative privileges, and malware should be kept from compromising the operating system. In other words, a user account may have administrator privileges assigned to it, but applications that the user runs do not inherit those privileges unless they are approved beforehand or the user explicitly authorizes.

User Account Control (UAC) features and Disabling Automatic creation of Administrative or "Hidden" shares are some of the security features of Windows Server 2008 and Windows 7 and Windows Vista, but it makes the user wondering about the cause of below UAC message flashing on his system, although that user is holding full administrative privileges on his/ her system.




Tasks that trigger a UAC prompt:-

Some of the followin g tasks which require administrator privileges are mentioned below:-
• Running an Application as an Administrator
• Changes to system-wide settings or to files in %SystemRoot% or %ProgramFiles%
• Installing and uninstalling applications
• Installing device drivers
• Installing ActiveX controls
• Changing settings for Windows Firewall
• Changing UAC settings
• Configuring Windows Update
• Adding or removing user accounts
• Changing a user’s account type
• Configuring Parental Controls
• Running Task Scheduler
• Restoring backed-up system files
• Viewing or changing another user’s folders and files
• Running Disk Defragmenter


References:-

http://technet.microsoft.com/en-us/library/cc709628(WS.10).aspx
http://en.wikipedia.org/wiki/User_Account_Control

Storing PST on network - Do not do it!

This article contains guidance on the limitations of using of personal folders (.pst) files over a local area network (LAN) or wide area network (WAN) link. Note that .pst files are not meant to be a long-term, continuous-use method of storing messages in an enterprise environment.
Recently, we have got couple of issues with one of our customer who kept their pst files (around 2000+ users only) over the network. DFS Replication also started getting numerous issues because of file handles operating system puts over that .pst gets once its accessed over the LAN/WAN. Consequently the VSS configured on those File Servers (DFS) also got the snapshots inflated due to high volume of activity on DFSRPrivate/ Staging area and there is no method that we can find to exclude that folder from snapshots being taken for VSS. This is also not supported by Microsoft.
What happens when you keep PST files and access it over the N/W:-
A PST file is a file-access-driven method of message storage. File-access-driven means that the computer uses special file access commands that the operating system provides to read and write data to the file. So even if there is a small change in the .pst file the complete file is being replicated and modified over the network through DFS-R. Consider the number of times the pst is accessed for around 2000+ users in the office hours.
This is not efficient on WAN or LAN links because WAN and LAN links use network-access-driven methods. These are commands that the operating system provides to send data to, or receive from, another networked computer. If there is a remote .pst file (over a network link), Outlook tries to use the file commands to read from the file or write to the file. However, the operating system must then send those commands over the network because the file is not located on the local computer. This creates lots of overhead and increases the time that is required to read and write to the file. Additionally, the use of a .pst file over a network connection may result in a corrupted .pst file if the connection degrades or fails. Consequently following issues may be experienced:-
A) Write operations can take approximately four times longer than read operations.
B) Outlook has slower performance than the Web Access Exchange Client.