Verify Services are Running

I want to write a simple application that will inform my clients on a minute by minute basis whether or not the services are up and running.  Most importantly I want to be able to connect to my SMTP and POP3 servers and ensure they are functioning as normal.

Is there a simple snipet of code that will connect to an IP address and Port to ensure that it is responding as expected (without violating its config - ie: dropping SMTP connection too early will ban the IP address from connecting again).

Thanks in advance.
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