Configure OWA 2003 Attachment Blocking

Daniel Petri

Jan 7, 2009

How do I configure attachment blocking in Outlook Web Access on Exchange Server 2003

MS KB 555001 by William Lefkovics (MS Exchange MVP) has more info:
There are 2 levels of file attachments for Outlook Web Access. Level1 attachments have file extensions that are prohibited from accessing by OWA. Level2 attachments have file extensions that can be accessed, but only if saved to the client’s file system first.
OWA is installed with a default set of file extensions for the two levels as shown in the following registry keys:

Level 1 attachments


Type: REG_SZ
Value Data:

ade,adp,app,asx,bas,bat,chm,cmd,com,cpl,crt,csh,exe,fxp,hlp,hta,inf,ins,isp,js,jse,ksh,lnk,mda,mdb,mde,mdt,mdw,mdz,msc,msi,msp,mst,ops,pcd,pif,prf,prg,reg,scf,scr,sct,shb,shs,url,vb,vbe,vbs,wsc,wsf,wsh

Level 2 attachments


Type: REG_SZ
Value Data:

ade,adp,asx,bas,bat,chm,cmd,com,cpl,crt,exe,hlp,hta,htm,html,htc,inf,ins,isp,js,jse,lnk,mda,mdb,mde,mdz,mht,mhtml,msc,msi,msp,mst,pcd,pif,prf,reg,scf,scr,sct,shb,shs,shtm,shtml,stm,url,vb,vbe,vbs,wsc,wsf,wsh,xml,dir,dcr,plg,spl,swf

Attachments listed should be separated by a comma with no space.

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