The Solid Rock Insurance Company has expanded its sales team into the field as traveling reps. The VP of Sales has requested that the new sales team will need a remote access solution. The organization is currently running Windows Server $2012$ R$2$ that can be configured as a remote access server as a VPN solution for the field reps. However, as the Director of IT you just reviewed what the organization has for VPN protocols which are available, but you need to determine the best protocol to provide. Since the field reps will be traveling large distances away from the office, they will be spending many nights per month staying in various hotels within their region. You realize that firewall compatibility will be a serious concern. Which VPN protocol will have the best compatibility with firewalls?