I am not able to configure 3 legged parameter, is there any other way to make DMZ? Please Help!!

Hi,

it is possible to crate a DMZ without the wizard!
Add a additionaol NIC to the TMG Server. Create a new network and network relationship (NAT or ROUTE) in the TMG MMC and Firewall policies to allow traffic between the DMZ and other networks like INTERNAL and EXTERNAL:
http://www.isaserver.org/articles-tutorials/configuration-general/TMG-Back-Basics-Part5.html

Hi thanks for your reply.

will it create the DMZ or parameter network to secure my internal network?

Hi,

Yes, it will create the DMZ network.

Best Regards,

Joyce