How to release front-end web server to the network

I have successfully completed the deployment of three layers of topological structure

Database management center front-end web server and domain firewall all open

I want to achieve in the home can access sharepoint

My front end server has been added to the field and join to the server fields two pieces of card

IP: 192.168.1.100 IP 172.16.1.100

Management center mapping port ready to mapping to 172.16.1.100

Through the TMG release its peripheral IP 172.16.1.100 public network analytic the domain name to the peripheral IP

The deployment method is feasible? Safe?

I have two questions

If the front-end web server back domain is more safe? Front-end web server back domain words will be able to realize the connection to the server field?

SharePoint configuration of outbound agreement port? TCP UDP