I keep getting this message from Norton Security: "the computer 10.0.0.159 is attempting to access your computer. Do you want to allow this connection?" What does this mean and what should I do?

You may find this article interesting reading:

Effective defenses against malware and other threats

Leprechaun4 wrote:

The Norton Security Software comes with my Comcast subscription. Do you have any suggestions on what I could use instead?

You don't need any security software on a Mac beyond what is built in.

Where are you seeing this? Do you run any Norton software?

If you're not running Norton, it's a scam.

If you are running Norton, get rid of it.

Remove it. It's garbage.