Android studio Gradle依赖库下载url

I develop android applications via Android Studio. And I would like to use 3 party libraries but I am working in a safe network which blocks all the internet except few which are specified by IT admin. I do NOT want to work with offline gradle option (Settings -> Gradle -> offline work). I would like to use gradle as if I got internet. To do that I need know which url is required, and tell IT admin open this spesific url. My question is which link or links I require ?I develop android applications via Android Stud