As a server administrator, you can use Central Administration to restrict certain kinds of files from being uploaded or retrieved, based on the file extension. For example, a file with the .exe file extension can potentially contain code that runs on client computers when the file is downloaded. If files with the .exe file extension are blocked, users can neither upload nor download a file with the .exe extension. By blocking this file type, potentially dangerous content in the .exe file cannot be downloaded and run on client computers.
By default, several standard file extensions are blocked, including any file extensions that are treated as executable files by Windows Explorer. Files with curly braces { or } are also automatically blocked. The file extensions blocked by default are shown in the following table.
FILE 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 (Visual Basic Scripting Edition (VBScript)) 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 |