tcp window size

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\ interface-name

Data type	Range	Default value
REG_DWORD	0x0–0x3FFFFFFF ( bytes )	(See description.)

Description
Determines the largest TCP receive window that the system offers. The receive window is the number of bytes a sender can transmit without receiving an acknowledgment. This entry overrides TCP's negotiated maximum receive window size and replaces it with the value of this entry.
TCP uses a receive window that is four times the size of the maximum TCP segment size (MSS) negotiated during connection setup, up to a maximum size of 64 KB. TCP for Windows 2000 also supports windows scaling, as detailed in RFC 1323, TCP Extensions for High Performance. Scaling enables TCP to provide a receive window of up to 1 GB.
For Ethernet networks, the default value of this entry is 0x4470 (17,520, or 12 segments of 1,460 bytes each). For other networks, the default value is 0xFFFF (65,535) unless 0xFFFF is larger than:

• Four times the maximum TCP data size on the network; and
• 0x2000 (8,192) rounded up to an even multiple of the network TCP data size.

Note
This entry determines the maximum receive window size for this interface. When configuring this interface, this entry takes precedence over the GlobalMaxTcpWindowSize entry, which establishes a maximum window size for all interfaces.
Windows 2000 automatically uses windows scaling if the value of this entry is greater than 64 KB. To disable windows scaling, set the value of the Tcp1323Opts entry to 0 or 2.
Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry

System File Checker: Run sfc /scannow & Analyze its logs in Windows 7 | 8

he System File Checker or sfc.exe is a utility in Microsoft Windows located in C:\Windows\System32 folder. This utility allows users to scan for and restore corrupt Windows system files.

System File Checker

In Windows 8, Windows 7 & Vista, the System File Checker is integrated with Windows Resource Protection, which protects registry keys and folders as well as critical system files. If any changes are detected to a protected system file, the modified file is restored from a cached copy located in the Windows folder itself.

So if at any point of time if you find that you have hacked some system files or maybe applied some tweaks or replaced system files, maybe while customizing your Windows, and you now find that your Windows is not working properly, you may want to consider running this utility first, before trying a System Restore. To do so, you will have to first open anelevated command prompt window.

To run the System File Checker in Windows 8, Windows 7 or Windows Vista, type cmd in start search box. In the result, which appear, right click on cmd and select Run As Administrator.

Run sfc /scannow

In the command prompt window which opens, type sfc /scannow and hit Enter.

The sfc utility will run for a while and if any corruptions are found, replace them on re-boot.

In case you are unable to start the System File Checker and you instead get the “Windows Resource Protection Could Not Start the Repair Service” error, you may want to check up if your Windows Modules Installer service has been Disabled. To do so, type services.msc in start search and hit Enter. The status of this services should be set to Manual. Alternatively, you can also download our very useful freeware utility FixWin and click on the System File Checker Utilitybutton. This will run sfc.exe.

Some more sfc switches:

Scan once at next boot:   sfc /scanonce
Scan at every boot:  sfc /scanboot
Purge File Cache:  sfc /purgecache
Return to Default Setting:  sfc /revert

You can also use the sfc.exe program to help you troubleshoot crashes that occur in the user mode part of Windows 7 & Vista. These crashes may be related to missing or damaged operating system files. To do so you may have to access the log files.

How to view the log file.

The sfc.exe program writes the details of each verification operation and of each repair operation to the CBS.log file. Each sfc.exe program entry in this file has an [SR] tag. The CBS.log file is located in the %windir%\Logs\CBS folder.

You can search for [SR] tags to help locate SFC.exe program entries. To perform this kind of search and to redirect the results to a text file, follow these steps:

Click Start, type cmd in the Start Search box, right-click cmd in the Programs list, and then click Run as administrator.

Type the following command, and hit Enter:

findstr /c:”[SR]” %windir%\logs\cbs\cbs.log >sfcdetails.txt

The sfcdetails.txt file includes the entries that are logged every time that the SFC.exe program runs on the computer.

How to interpret the log file entries:

The sfc.exe program verifies files in groups of 100. Therefore, there will be many groups of SFC.exe program entries. Each entry has the following format: date time entry_type details. For more details on how to interpret, visit KB928228.

Go here if you find that System File Checker (SFC) cannot repair corrupted member file.

http://www.thewindowsclub.com/how-to-run-system-file-checker-analyze-its-logs-in-windows-7-vista 

How to enable ROOT password in Ubuntu 12.0.4

1. Open a terminal

2. Type sudo passwd -u root

(This is enable root account password expiry time)

3. Type passwd root

(This command is for changing the ROOT password)

4. Please enter the password as required by you

5. Again enter the password as the same entered first time.

6. Type su

(Now it would ask for ROOT password give your password and enter into ROOT.

Cannot add to the server Junk E-mail Lists, you are over the size allowed on the server. The Junk E-mail Filter on the server will be disabled until your Junk E-mail Lists have been reduced to the size allowed by the server

Microsoft Exchange has a limit to the size of the rule where your different "junk" lists are stored. By default, the limit is 510 KB.

In relation to this limit, there are four known causes for the above errors.

• You have a large number of entries in your Safe Senders, Blocked Senders, and Safe Recipients lists
  
  By default, you have a cumulative limit of 510 KB for all of your junk e-mail lists. If you have a large number of entries in these lists (cumulatively), then you may receive the above error when you attempt to add more items to the lists.
• The Max Extended Rule Size registry value is incorrectly configured on the Exchange server
  
  On an Exchange server, you can configure the following registry data:
  
  Registry key: HKLM\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
  Value: Max Extended Rule Size
  Type: DWORD
  Data: an integer specifying the maximum size, in bytes, you want to allow for the junk e-mail rule
  
  The value you enter in the registry is interpreted as the maximum rule size in bytes. Therefore, if you want to specify a limit that is higher than the default 510 KB, you need to enter a value higher than 522240 (decimal).
  
  The above error can occur when you inadvertently specify a value lower than the default limt. For example, you enter a value of 1024 under the assumption that this is doubling the default limit of 510 KB. Since the value you enter is interpreted as a number of bytes, a value of 1024 means you have configured a limit of 1024 bytes, substantially lower than the default limit of 510 KB.
• The PR_RULE_MSG_STATE property of the Junk E-mail Rule message is incorrectly configured
  
  With an Exchange mailbox, your junk e-mail settings are stored in a hidden message in the associated contents table of your Inbox folder. The subject of this hidden message is Junk E-mail Rule. This message has a property calledPR_RULE_MSG_STATE and the default value on this property is 49 (decimal) or 0x31 (hexadecimal). If you then disable junk email filtering in Outlook Web App, the value of this property becomes 48 (decimal) or 0x30 (hexadecimal). Therefore, if the value specified on this property is something other than 48 or 49 (decimal), then you may receive the above error.
• The "Also trust e-mail from my Contacts" option is enabled in Outlook
  
  On the Safe Senders tab of the Junk E-mail Options dialog box you can configure the Also trust e-mail from my Contacts option. If enabled, and you have a large number of contacts in your Contacts folder, you may inadvertently exceed the 510 KB limit on your mailbox. With this option enabled, Outlook attempts to add all of the email addresses for your contacts to the Safe Senders list. 

http://support.microsoft.com/kb/2669081