Name:Little Snitch (Free)
URL:https://www.obdev.at/products/littlesnitch/index.html
Utility:This free tool - 

• Shows a connection alert, whenever an app attempts to connect to a server on the internet
• Allows decide whether to allow or deny the connection 
• Prevents data transmission without consent 
• Remembers the decisions and applies automatically in future 
• Prevents Trojans, malwares and tracking programs from sending our data to their servers for malicious ends
• Makes internet connections visible and gives greater control