From a security perspective, 7211.com Mail Server would reject inbound mails containing attachments with any of the following file extensions:
.ade |
.adp |
.adt |
.app |
.asd |
.asp |
.asx |
.bas |
.bat |
.bin |
.btm |
.cab |
.cbl |
.cbt |
.cgi |
.chm |
.cil |
.cla |
.clas |
.class |
.cmd |
.cpe |
.cpl |
.crt |
.csc |
.csh |
.css |
.cvp |
.dll |
.dot |
.drv |
.exe |
.fon |
.fxp |
.hlp |
.hta |
.htr |
.inf |
.ini |
.inp |
.ins |
.isp |
.jar |
.js |
.jse |
.keyreg |
.ksh |
.lib |
.lnk |
.mda |
.mdb |
.mde |
.mdt |
.mdw |
.mht |
.mhtm |
.mhtml |
.msc |
.msi |
.msp |
.mst |
.mp3 |
.nte |
.nws |
.obj |
.ocx |
.ops |
.ov |
.pcd |
.pgm |
.pif |
.pl |
.pm |
.prg |
.scr |
.sct |
.shb |
.shs |
.slb |
.smm |
.swf |
.swt |
.sys |
.vbe |
.vbs |
.vbx |
.vir |
.vmx |
.vxd |
.wmd |
.wms |
.wmz |
.wsc |
.wsf |
.wsh |
.xms |
.com |