How to a firewall rule that only allows traffic in from a specific real world IP?

Question

I am currently running 17.0.3 MR-3 
 
 I would like to create a firewall rule from WAN to LAN that will allow RDP traffic from a specific real world IP. Basically, I want to be able to RDP into my home computer from work, but do not want to have the RDP port available to everyone on the Internet. 
 
 I am familiar with Fortigate appliances where I could create an Object for my work IP which could then be configured into an allow Policy, but I'm having trouble figuring out how to do this in the Sophos environment. 
 
 Any assistance that the community can offer would be greatly appreciated. 
 
 Thanks!

ShunzeLee · Accepted Answer

You may use the "Allowed Client Networks" to limit the access of public IP.

lferrara · Answer

guruerror , 
 as Ian suggested, follow the B and change the "allowed client networks" from any to the real source public IP. 
 Regards