TMG Server Firewall Rule

Hi experts,

I am trying to deploy Forefront TMG in a Virtualized Environment.

The software I am using is Oracle VM VirtualBox.

I have made 2 server machines . One is a domain controller and on the
other machine I have installed FTMG 2010. The TMG server is part of the domain.
It has two NICs one for WAN & the other one for LAN
On the tmg server I have made a firewall rule that allows all outbound traffic
to an AD user.

On another Win7 Virtual Machine that is joined to the domain. I logged in as a user
and inthe internet options of IE I configured the proxy settings that points
to my TMG Server. But nothing is showing up even the websnse page.

I just shows 'Internet Explorer cannot show the webpage'.

Can anybody help me where I m mistaking....!!!