access sharepoint site collection on internet

I'm working on a SharePoint deployment that is meant to be accessed over the internet. I already have a public IP and also a domain name pointing to the public IP, I created an alternate access mapping on sharepoint for the pubic IP and the domain name, I also created a binding on the web application on the iis. With all these, I still can't access SharePoint on internet, it only bringsup the authetication dialogue and after 3 attempts the page just go blank. Please help

Spruce Integrated