I have created a server with dynamic ip and used the no-ip to create a DNS Host name so that my ip can change automatically when i restart the modem. So my problem is that i restarted the modem my ip is updated by no-ip client but the game tracker has same old ip and i have even entered the DNS name in the manage server. And i yes i have checked the ports are open on the right ip, so my question is that how long gametracker takes to refresh ip from a DNS host name or do i need to create a new server.

We resolve the DNS name daily. If this server stops responding to stats requests, then we resolve the DNS name more frequently.