There is a requirement to block access to a particular website and you would like to know if DLP endpoint agent can be leveraged to achieve this.
DLP 15.x
DLP solution is designed to protect sensitive data from reaching the websites but it cannot block access to the website. A user can send data to a website via file uploads, clipboard paste, etc and DLP will monitor or block this transfer if it violates a policy.
If you are looking for a solution to block access to a website then you should consider some other security product which offers this capability.