Perform the following operations on the NGFW:
Configure a source NAT policy, in which the source and destination security zones are the same as those of the intranet user and server. The source NAT policy translates the source IP address of the intranet user into the public IP address of the intranet server.
Configure a static mapping policy to translate the public address into the private address of the intranet server. The packets sent by the user to the server carry the server's public address as the destination address.