Roaming client update problem

Dear Support,

I am using roaming client package on laptop machine. Now i want if my client machine is going outside of my offical network. At this situation my client machine connect with my office SEPM manager server. I have a public ip to connect ouside network client machine with my SEPM server. So please provide the procedure to how to connect client with my offical public ip address.

I was also change the live update policy and given public ip address on internal liveupdate server but it's want URL also so please help me how to do this.