I need to know something about Ftp server

when we trying to connect to ftp server from the client side (cute-ftp software) , there is some delay(15 sec) before the login windows appears. i know this is name resolutin problem .I have put client ip address and the name of the machine in the hosts file (/etc/hosts) under
linux 6.2 after that problem has been resolved

I have did the same thing in linux 7.x but delay is still over there, i dont why .