The server will not be the part of the internal network thats ok, and has been already agreed upon.

As this application will be directly accessing the database server and yes there will be data coming in and out from the server and similarly at the user end too.

But still i am a little worried about the threat to that server as it will be open for everyone and will not be a on private network.... I will be using a firewall in front of it and are there any other things i can implement to make sure thats its more safe and scure.