DCOM Server Process Launcher
Provides launch functionality for DCOM services.

Note the following things will fail if this service is not running:
  • The builtin defrag will fail to work, and if running defrag from the command line one gets this error:
    Windows cannot connect to the Disk Defragmenter engine
  • System Information (MsInfo32) will fail to work and give this error:
    Can't Collect Information
    A network error occurred in connecting to Windows Management Instrumentation. Ensure that your network connection is functioning properly.
  • Disk Management will fail and give this error:
    The RPC server is unavailable
  • The install of new applications will fail and give this error:
    The InstallShield Engine (iKernel.exe) could not be launched.
    The RPC server is unavailable.
 
DHCP Client
DHCP(Dynamic Host Configuration Protocol) is used to store network configuration at a central place (DHCP Server). The DHCP client will automaticly contact the DHCP server (Port 67) and acquire what network configuration it should use.
  • Client IP-Address
  • Gateway IP-Address
  • Primary & Secondary DNS Server IP-Addresses
Note if the computer is part of a domain and dynamic DNS (DDNS) is used, then one should be aware that the DHCP Client is also responsible for registering the computer in the DNS.

Note if the client is configured in the network properties to acquire its TCPIP configuration through TCPIP, and there is no DHCP-Server available to serve an IP-Address to the client, then the client will block while timing out.

More Info Microsoft DHCP
 
 
Directory Replicator / File Replication Service
It provides control replication / synchronization of directories and files among multiple servers. It is used by the Distributed File System (DFS) to automaticly synchronize file catalogs. It is used by the Active Directory to automaticly synchronize Domain Controllers.
 
Distributed File System
The DFS manages logical volumes distributed across a local or wide area network. It maintains a large catalog of all the files with their physical location. The catalog is usually replicated on multiple machines and being synchronized using File Replication Service. The catalog enables clients to requests a file using a logical name, without needing to specify the exact machine that stores the actual file.
 
Distributed Link Tracking Client
Maintains shortcuts and Object Linking and Embedding (OLE) links to target files in the following scenarios (When placed on NTFS partition):
  • The link source file is renamed.
  • The link source file is moved to another folder on the same volume or a different volume of the same computer.
  • The link source file is moved to another computer in the network.
  • The shared network folder containing the link source file is renamed.
The following scenarios can also be handled if in a domain where the Distributed Link Tracking Server is running:
  • The link source file is moved between computers
  • The computer containing the link source file is renamed.
  • The volume containing the link source file is moved to another computer within the same domain.
It performs these services by monitoring activity on the NTFS volumes and store maintenance information in a file called Tracking.log, which is placed in the root folder "System Volume Information".
 
Distributed Link Tracking Server
Stores information so that files moved between volumes can be tracked for each volume in the domain.

Note if disabling this service on the domain controller then the "NtfsDisableDomainLinkTracking" policy should be enabled to stop Distributed Link Tracking Clients from trying to reach it.
 
Distributed Transaction Coordinator
Coordinates transactions that are distributed across two or more databases, message queues, file systems, or other transaction protected resource managers.
The service listens on TCP port 3372 along with a ephemeral TCP port (Above 1023).

The service creates the file %SystemRoot%\system32\DTCLog\MSDTC.LOG for storing Transaction-related recovery information along with all other MS DTC recovery information (WinNT4 also uses Dtcxatm.log). If the location is faulty(non existing or no permission) or the MSDTC.LOG is corrupted, then it will keep the service from starting and give the error:
Event ID : 7024
Source : Service Control Manager
Description: The MSDTC service terminated with service specific error 3221229584.

Event ID : 4163
Source : MSDTC
Description: MS DTC log file not found. After ensuring that all Resource Managers coordinated by MS DTC have no indoubt transactions, please run msdtc -resetlog to create the log file.

More Info MS KB Q205069
 
To reset the log-file :
  1. If possible start the computer in safemode
  2. Open the the %SystemRoot%\System32\DTCLog folder. (Unless you have changed the default location)
  3. If a Msdtc.log file exists in the folder, rename it to Msdtc.old.
  4. Use Notepad to save an empty file as Msdtc.log in the folder.
  5. Open a CMD prompt and type: msdtc -resetlog and press Enter.
To change the location and reset the MSDTC.LOG in WinNT4:
  1. Click Start and Run... the command DAC to start the MSDTC Administrator Console
  2. On the Advanced-tab, one can change the location of the Msdtc.log
  3. Click Reset Log when done
To change the location and reset the MSDTC.LOG in Win2k:
  1. In the Control Panel open Administrative Tools and launch Component Services
  2. Expand Component Services-node and then in the Computers-node, right-click the computer that is generating the error (Usually My Computer) and select Properties
  3. On the Advanced-tab, one can change the location of the Msdtc.log (Default %systemroot%\System32\Dtclog)
  4. Click Reset Log when done
Note one can disable the mutual authentication between the DTC services on different computers (In case the two computers are not on the same domain):
[HKEY_LOCAL_MACHINE \SOFTWARE \Microsoft \MSDTC \Security]
TurnOffRpcSecurity=dword:00000001
 
DNS Client
The DNS Client acts like a local DNS server, and is used whenever an application requires to resolve a Domain Name System(DNS) name.

If an application wants to connect to www.google.com, then it requests the DNS client for it to convert it to an IP address. If the DNS client doesn't recognize the domain it passes the request to the network DNS Server (Port 53), but caches the reply for later use by the same or other applications and thus increases the speed of future DNS lookups and causes less load on the network DNS Server.

When using WinXP to logon to a domain one should register the domain server's IP as the primary DNS Server. If this is not done the login to the domain will be very slow.

When using Win2k/WinXP to logon to a WinNT4 domain one should enable Netbios over TCP/IP for the Internet Protocol in network properties on Win2k/WinXP as the WinNT4 domain doesn't use DNS.

Note in Windows XP this service keeps the same UDP connection open to make all DNS requests. In Windows 2000 the service opens/closes a UDP connection for each request. To make XP behave like Windows 2000 use this DWORD registry key:
[HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services \Dnscache \Parameters]
MaxCachedSockets = 0
 
Error Reporting Service
The Error Reporting Service provides an infrastructure for collecting, storing and reporting kernel mode, operating system and application faults to Microsoft.

One can configure the Error Reporting by going to Control Panel => System-Applet => Advanced-Tab => Error Reporting-Button
 
Event Log
This service tracks events and logs them, which makes it easier to diagnose cause of problems:
  • System log: Contains events from the Windows Operating System, usually a good place to look for a reason when a the system is acting funny
  • Security log: Contains events from the Audit watches, usually good place to see if someone is attacking your machine
  • Application log: Contains events from application, usually good place to see 3rd party application events (Though Windows also uses this log)
  • Directory service log (Win2k3): Contains events from the Windows Active Directory Service
  • File Replication service log (Win2k3): Contains events from the Windows File Replication service
  • DNS server log (Win2k3): Contains events from the DNS Server Service
Note one can change the location of the log-file for each eventlog:
[HKEY_LOCAL_MACHINE \System \CurrentControlSet \Services \Eventlog \LogName]
File = "C:\Foo\LogName.Evt"
 
Fast User Switching Compatibility
Allows several users to be simultaneously logged locally on the same machine, and then switch between each of these user's sessions.
The service is only started when a second user logs on to the machine.

To configure Fast User Switching go to Control Panel => User Accounts => "Change the way users log on or off".
 
FAX Service
Helps you send & receive faxes.
This service gets installed if fax capable modem is installed in your machine.









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