port80 is the port that you connect to on remote webservers. However the client port will
not be port 80.
For example if I want to visit mysite.com. My PC port will be a random number such as 55410 and I'll be connecting to port 80
My PC 55410 <-------> mysite.com 80
You can see this by visiting
IPChicken and looking at 'remote port'.
Easiest way to stop people voting over and over is just to remove the permission for guests to vote in polls.