DMZ server not able to access the SQL Sever

we are in process of Publishing our portal

following are the steps we used

Confgiure application and database server on one of the server APPS01

Configure the Web front end server in Dmz WFE01 And add this server in domain to configure and connect to the Database server

Later remove the ports from firewall that were used to access the DNS

now if i am trying to browse the localhost from

web front end i am getting "Cannot connect to the configuration database"

when i check the log  "Cannot generate SSPI Context"

either i am able to browse the Sharepoint application server and sites DMZ web front end server

actually i have to complete the SSL and external DNS configuration on dmz to publish it online portal

MCTS,ITIL