Configure OWA 2003 Attachment Blocking
Configuring Attachment Blocking on Exchange Server 2003 through Outlook Web Access
Outlook Web Access has two different levels of file attachments. Level 1 files cannot be accessed by Outlook Web Access, whilst Level 2 can be accessed if saved first. The two levels are set by a list of file extensions within registry keys.

Level 1 –
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMSExchangeWebOWA

Type – REG_SZ

Values –
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 –
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMSExchangeWebOWA

Type – REG_SZ

Values –
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

Article written by MyComputerAid.com