Thank You for your answer.

My Problem:
The client can allways connect to FB server undependend on port
number given by connection string even valid or unvalid.

I have been readed all document and tested all possibilities before
sending messages. But I find a way very simple.

Uninstall all Firebird and Interbase related products.
Install Firebird.

Belive me there is no problem after two days without sleeping.
Works very good :)

My suggestion is "lnstalling firebird after all of install process".

Thanks & Regards
Safak