I can create user privilege via domain name instead of ip address?

[fei lee]

Dear Sir/Madam,

i have the server as following:
[CLIENT]
domain name: db.host.com
ip address : 211.133.145.123

[MYSQL SERVER]
ip address : 211.134.152.321

Then I created the following user privilege with domain name on mysql server:

CREATE USER 'user1'@'db.host.com' IDENTIFIED BY '***';
GRANT USAGE ON * . * TO 'user1'@'db.host.com' IDENTIFIED BY '***' WITH MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0 ;

Then i tried to connect to the mysql server from db.host.com
[yunghee@localhost ~]$ mysql -h 211.134.152.321 -u gsm -p
Enter password:
ERROR 1045 (28000): Access denied for user 'user1'@'211.133.145.123' (using password: YES)

Then i found that if i create user with ip address instead of domain name, i can login to the mysql server.

My question is, can i create user privilege via domain name instead of ip address? This is because the ip address of my domain name is dynamic.

Thanks for every advice!

Lee