Hi Keshwani,
first le us know which version of DLP u wanted to install so that we can provide details.
Still find the prereqisite for DLP 11.6
https://www-secure.symantec.com/connect/forums/2-tier-install-dlp-116-needs-more-2-servers
https://www-secure.symantec.com/connect/forums/dlp-116-system-requirement#comment-8142681
https://www-secure.symantec.com/connect/forums/symantec-dlp-system-requirements