I have a consultant that needs to connect to a server via RDP on our network on a regular basis. A VPN solution will not work so I created a port on the SonicWall and made a NAT that forwarded the request onto the RDP connection on the server. That works fine but I have to open and close the port on the firewall each time they want to connect to the server. I would like to make it where only the consultants public IP has access to that port so that I don't have to open and close the NAT rule everytime they want to connect.
How can I configure the firewall to allow only that public IP to connect to the forwarding port on the SonicWall?