Connection test services

I have a client that I need to monitor to make sure they stay online. I will probably need to make a two part application for this:

• A server that will send out something of a heart-beat signal and wait a specified interval to make sure it gets a reply back.
  
• A client that will answer the heart-beat at a specified interval.

If the heartbeat isn't answered, then I think there should be an event that occurs.

• The site downage is recorded to a database
• an email should be sent to parties responsible for the sites up time.
• An email should be sent to aboveSHIFT