I wanted a few development sites so I installed Mamp Pro and changed my router settings and got a few vhosts set up in DynDNS and finally got it where I could see the Install page for C5 in both the localhost and an external PC. If I fill out the install page on the local computer, entering localhost as the server, I can see C5 properly on the local computer. However I get an error message if I use try to access it from the PC. The DynDNS url worked before c5 was installed. Once C5 is installed it doesn't work. My guess is that the problem is the host type and permissions. The error message in IE is "Website declined to show this page. Most likely cause- the website requires you to log in." I gave the user full permissions so I'm out of ideas.