Turn off the Norton alerts as they are all a waste of space/time. Norton and all the other firewalls report normal internet activity as 'attacks'. They are nothing like an attack and some very cynical people would say Norton do this to 'show' the 'effectiveness' of their product;-))).
It is interesting to note that the free version of ZA suddenly stops reporting these attacks when the paid for version is installed. You will never get hacked on a home computer. I never use a firewall so am absolved from the angst of the alerts ;-))