With Exchange 2013, do we need to install exchange aware antivirus on machine for scanning, are built-in mechanisms are enough. is there any alternative for third party antivirus software. Reason behind query is with Windows server 2012 i guess we can deploy antivirus software using System center. So by this dependency on other third party product reduces for easy management & all integrated approach.

Only you or the decision makers in your organization can decide what's enough. Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

yes agree but can we consider builtin spam scanning with Exchange 2013 as a complete alternative to third party exchange aware scanning products.