By default the following file extensions (.txt .doc .xls .ppt .java .c cpp .h .js) will retain their original file type when Quarantined and replaced with a marker file.
To adjust the file marker extension that is left in place of a file that has been quarantined you will need to modify the following file on your Network Discover server: ProtectRemediation.properties
ProtectRemediation.properties is located in C:\Program Files\Symantec\DataLossPrevention\DetectionServer\xx.x.00000\Protect\config (/opt/DataLossPrevention/Protect/config for Linux)
Modify the following line:
com.vontu.protect.extensions_not_replaced=txt|doc|xls|ppt|java|c|cpp|h|js
For example if you want all replaced marker files to be filename.doc.txt OR filename.ppt.txt set the parameter as follows:
com.vontu.protect.extensions_not_replaced=txt
To complete the change, save the file, then restart the Symantec DLP Detection Server Service.