.Net runtime optimization service

Hello Forum, What exactly is C:\windows\microsoft.net\framework\v4.0.30319\mscorsvw.exe ? After the windows update yesterday another firewall rule appeared. Do I need this rule to run or can I block it? I have Googled and nothing about this. I fiqured maybe the techies from Norton could help me fiqure this out. Do I need this rule to run? Thank you, Paul