The port 2688 isn't standard http, so I assume you're using a development server (IIS Express or VS Development server)? If so, you could look that
- the firewall of your Windows system allows external access to that port
- the server listens on all IPs (you can check this using the netstat command)
Edit:
If netstat -an lists a line like
TCP 0.0.0.0:2688 <hostname>:0 LISTENING
it's listening on all IPs (127.0.0.1 and the ips your PC has. If instead of 0.0.0.0 there is a specific ip such as 127.0.0.1, the server just listens on that specific port / ip combination
Edit 2:
Cassini cannot be accessed from another PC ( http://weblogs.asp.net/ryangaraygay/archive/2008/04/19/asp-net-development-server-cannot-be-accessed-using-non-localhost-url.aspx ) So you would have to switch to IIS Express or IIS