Thank you for your answer
I know only that a Domain has a Dedicated IP, which means that if you write IP from domain you have to convert to Domain and that is better for SEO, but the topic does not matter.
My problem is:
I have a Server with an IP and Domian.
my hostname is: server.mydomain.com
i want to be my main domain mydomain.com means if i write my server ip on Browser convert to mydomain.com not to server.mydomain.com
Thank you for your help.