Does anyone know if you can configure a hairpin NAT on a Cisco SA540? I can configure NAT for outside users to connect to my mail server. And my internal secured network users connect to the mail server via the internal IP address. But I have users on a guest Vlan that cannot connect to the internal IP address of the mail server so they are trying to use the public IP. The guest users are on the LAN zone. When I create a LAN/WAN zone for the external IP I don't get the option to configure the internal IP address.