Why Are these files Blocked ?
Its nothing but security Threats to confidential Data .
By default, many file types are blocked, including file types that are treated as executable by Internet Explorer. Files, whose names include braces, (for example, filename.{doc}) are also blocked by default.
The following table shows the file types that are blocked by default and their corresponding file name extensions.
| File name extension | File type |
|---|---|
| .ade | Microsoft Access project extension |
| .adp | Microsoft Access project |
| .app | Application file |
| .asa | ASP declarations file |
| .ashx | ASP.NET Web handler file. Web handlers are software modules that handle raw HTTP requests received by ASP.NET. |
| .asmx | ASP.NET Web Services source file |
| .asp | Active Server Pages |
| .bas | Microsoft Visual Basic class module |
| .bat | Batch file |
| .cdx | Compound index |
| .cer | Certificate file |
| .chm | Compiled HTML Help file |
| .class | Java class file |
| .cmd | Microsoft Windows NT command script |
| .com | Microsoft MS-DOS program |
| .config | Configuration file |
| .cpl | Control Panel extension |
| .crt | Security certificate |
| .csh | Script file |
| .dll | Windows dynamic-link library |
| .exe | Program |
| .fxp | Microsoft Visual FoxPro compiled program |
| .hlp | Help file |
| .hta | HTML program |
| .htr | Script file |
| .htw | HTML document |
| .ida | Internet Information Services file |
| .idc | Internet database connector file |
| .idq | Internet data query file |
| .ins | Internet Naming Service |
| .isp | Internet Communication settings |
| .its | Internet Document Set file |
| .jse | JScript Encoded script file |
| .ksh | Korn Shell script file |
| .lnk | Shortcut |
| .mad | Shortcut |
| .maf | Shortcut |
| .mag | Shortcut |
| .mam | Shortcut |
| .maq | Shortcut |
| .mar | Shortcut |
| .mas | Microsoft Access stored procedure |
| .mat | Shortcut |
| .mau | Shortcut |
| .mav | Shortcut |
| .maw | Shortcut |
| .mda | Microsoft Access add-in program |
| .mdb | Microsoft Access program |
| .mde | Microsoft Access MDE database |
| .mdt | Microsoft Access data file |
| .mdw | Microsoft Access workgroup |
| .mdz | Microsoft Access wizard program |
| .msc | Microsoft Common Console document |
| .msh | Microsoft Agent script helper |
| .msh1 | Microsoft Agent script helper |
| .msh1xml | Microsoft Agent script helper |
| .msh2 | Microsoft Agent script helper |
| .msh2xml | Microsoft Agent script helper |
| .mshxml | Microsoft Agent script helper |
| .msi | Microsoft Windows Installer package |
| .msp | Windows Installer patch package file |
| .mst | Visual Test source files |
| .ops | Microsoft Office profile settings file |
| .pcd | Photo CD image or Microsoft Visual Test compiled script |
| .pif | Shortcut to MS-DOS program |
| .prf | System file |
| .prg | Program source file |
| .printer | Printer file |
| .pst | Microsoft Outlook personal folder file |
| .reg | Registration entries |
| .rem | ACT! database maintenance file |
| .scf | Windows Explorer command file |
| .scr | Screen saver |
| .sct | Script file |
| .shb | Windows shortcut |
| .shs | Shell Scrap object |
| .shtm | HTML file that contains server-side directives |
| .shtml | HTML file that contains server-side directives |
| .soap | Simple Object Access Protocol file |
| .stm | HTML file that contains server-side directives |
| .url | Uniform Resource Locator (Internet shortcut) |
| .vb | Microsoft Visual Basic Scripting Edition file |
| .vbe | VBScript Encoded Script file |
| .vbs | VBScript file |
| .ws | Windows Script file |
| .wsc | Windows Script Component |
| .wsf | Windows Script file |
| .wsh | Windows Script Host settings file |
Add or remove blocked file types
Use this procedure when you want to prohibit files of a specific type from being saved or retrieved from any Web application on a server.
To add or remove blocked file types by using Central Administration
-
Verify that you have the following administrative credentials.
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You must be a farm administrator on the server.
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You must be a farm administrator on the server.
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In Central Administration, click Security.
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On the Security page, in the General Security section, click Define blocked file types.
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On the Blocked File Types page, if you want to change the selected Web application, on the Web Application menu, click Change Web Application. Use the Select Web Application page to select a Web application.
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Do one of the following:
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To block an additional file type, scroll to the bottom of the Type each file extension on a separate line text box, type the file extension you want to block, and then click OK.
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To stop blocking a file type, select a file type from the list, press the Delete key, and then click OK.
Note : You do not have to type a file extension in the list in alphabetical order. The next time you open the list, the file extension you added will be correctly sorted in alphabetical order.
Reference : http://technet.microsoft.com/en-us/library/cc287701%28v=office.14%29.aspx
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To block an additional file type, scroll to the bottom of the Type each file extension on a separate line text box, type the file extension you want to block, and then click OK.
