This question already has an answer here:
I just switched from Windows 8 to Ubuntu 13.04. I installed UFW GUI interface for the firewall. In the listening report it shows the something called dhclient and avahi-daemon running in a few ports.
I google both, but could not find a clear answer on if I need them and if not how do I turn them off. The only things I use my home computer for is the internet (Midori browser), steam and arduino.
Any help would be appreciate.