I'll say yes.
Just on the input side.
If you were to use a product like zone alarm and let it notify you of every input probe you'll see a bunch.
These probes are looking for machines with open doors/ports.
Someone with bad intent could set up an automated probe to look for machines with open doors.
If that's you then you've got a problem.
Keep all your doors closed and the probes go away...looking for a machine that's an easy target.
I have a quick question. I have a dial-up connection. I leave it connected and idle for long periods of time. Am I leaving myself open to viruses, mal-ware, or any of the nasties?